8A下各单元答案(2)(1)
2019-2020牛津英语8A 期中复习专题训练--翻译句(有答案)
牛津英语8A 期中复习专题训练--翻译句子中译英1. 不仅Peter的父母在把这墙涂蓝,Peter 也正在涂。
__________________________________________________________________________ 2. 我建议她继续用水把杯子装满。
__________________________________________________________________________ 3. 米莉喜欢把草莓切成小块然后把它们一起搅拌。
__________________________________________________________________________ 4. 你最好不要再犯同样的错误了。
__________________________________________________________________________ 5. 吉尔的爸爸用了两个小时独自装饰了他的卧室。
__________________________________________________________________6.把牛奶装进杯子,然后把它放在空气里一段时间。
7. 你应该努力学习而不是痴迷于打电脑游戏。
8. 他经常用剪刀把纸剪成一片片的来取乐。
9. 坏掉的灯很危险,所以我们最好赶快修好它。
10.没有阅读说明最好不要开始你的工作。
_________________________________________________________11.他正试着在餐厅里装一个更亮的灯。
___________________________________________________________________12. 昨天下午他没有出席那个会议,却去了一个朋友家。
___________________________________________________________________13. 他不能相信自己的眼睛,因为一个八岁的男孩在画画竞赛中得了第一名。
单元测试卷8A Unit 1含答案
8A Unit1单元测试卷第I卷(选择题共40分)第I卷共35小题,答案请按要求写在答题卡上一、单项选择(本题共15小题;每小题1分,满分15分)从A、B、C、D四个选项中,选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。
( )1.______ boy called Tom never tells lies. What ________ honest boy he is!A. The, aB. The, anC. A, anD.A, /( )2. He is very _________ because he often gives money to people in need.A. cleverB. funnyC. generousD. honest( )3. Don’t ______ her lies. She always tells lies. Nobody in my class ______ her.A. believe, believesB. believe, trustsC. trust, trustsD. trust, believes ( )4. The girl is kind to ________ and she never plays tricks on __________.A. everyone; anyoneB. everyone; everyoneC. anyone; anyoneD. anyone; everyone ( )5. There is ___________ in today’s newspaper, so I don’t want to read it.A. nothing interestingB.interesting nothingC.something interestingD. anything interesting( )6. It made me quite ________ when I thought of my sick dog.A. worryB. worry aboutC. worriedD. worrying( )7. My cousin likes _______ jokes and he never _______ bad things about others..A. saying, tellsB. to tell, sayC. telling, saysD. to say, tells( )8.The Voice of China became one of ________ TV ______ last year.A. the most popular, showsB. more popular, showC. much popular, showD. the popularest, shows( )9.Riding a bike to school takes ___________ time than walking.A. fewerB. lessC. moreD. least( )10,The price of this TV set is the __________ of the three.A. highestB. cheapestC. most expensiveD. biggest( )11. He always _______ others and seldom thinks of himself. How kind he is!A. cares aboutB. laughs atC. worries aboutD. looks for ( )12.I’m still too hungry. Please give me _______________ hamburgers.A. more twoB. another twoC. anotherD. two other( )13. I don’t know who __________ the bo y stand here. How poor he looks!A. toldB. makesC. asksD. wants( )14. ---Thank you very much for giving me this beautiful card.---_________________________________A. Really, do you like it?B. It’s only a little thing.C. Is it beautiful?D. I’m glad you like it.( )15. --- I think Betty is very helpful.---_____________ She never gives her seat on the bus to people in need.A. I agree.B. Me too.C. I’m afraid she isn’t.D. Great!二、完形填空(本题共15小题;每小题1分,满分15分)请认真阅读下面短文,从短文后各题所给的A、B、C、D四个选项中,选出最佳选项,并在答题卡上将该项涂黑。
2024人教新目标八年级下册英语Unit 2Section B 2a-3b课后练习及答案
Unit 2 I’ll help to clean up the city parks? Section B ( 2a- 3b)课后练习课程基本信息学科英语年级七年级上册课题Unit 2 I’ll help to clean up the city parks? Section B ( 2a- 3b)使用教材人教新目标出版日期2013.05学生信息姓名学校班级学号学习目标1. To learn to understand the word’s me aning by knowing what part of speech a word is2. To learn to write a letter or an e-mail to the place where you volunteer3. To learn to use some useful words, expressions and patterns in the passage:set up, make a (big) difference, excited, because of, …课后练习基础过关一、单项选择。
1.They are going to ___________ a new bridge over the river.A. give upB. hand upC. set upD. cheer up2. My friend Mary met friend of ________ in the library yesterday.A. sheB. herC. hersD. me3.Can you help me send the letter _______ Mary.?A. toB. forC. withD. of4. I find ______ not easy for us to train a dog.A. thatB. itC. thisD. one5. If I have a good sleep, I ______ work out the problem.A. canB. am able toC. will be able toD. will can6.She is a friend of ________. We are good friends.A. meB. IC. myD. mine二、单词拼写。
牛津译林版英语8AUnit1单元检测卷含答案(6份).docx
8A Unitl Friends 单元测试卷(A)(时间:60分钟满分:100分)一、单项选择。
(每小题1分,计10分)( )1.1 have ________ to tell you about my best friend ・A. something otherB. other somethingC. something elseD. else something ( )2・ My friend Jack looks fine ・ He always ______ a smile ________ his face.A ・ have; on B. with; in C ・ puts; in D ・ wears; on( )3. English Weekly invites students _________ vote ________ t he most attractive (有吸引力的)reader.)4. Sandy doesn't know how to make a plan. You can give her some _________A. abilityB. secretsC. adviceD. problems)5. Would you please ________ y our shoes on the floor?)7. When the boy walks ________ the table , he often knocks the things ___________ i t. A. pass; off B. past; offC. pass; on )8. -Do you know what he ________ t wo years ago?-Yes. He was fat then.A. likedB. is likeC. likes )9. Its known that Suzhou is ________ in the world.A ・ one of the most beautiful countriesB ・ one of the beautiful countriesC. one of the most beautiful citiesD. one of the most beautiful city( )10. My roommate is a girl _________ round eyes and long hair.A. hasB. withC. hadD. is having二、完形填空。
牛津8A_Unit1单元检测(含答案)
牛津8A Unit1单元检测二、选择填空(15分)( ) 1. My brother is two years ________ than I.A. oldB. olderC. oldestD. the oldest( ) 2. I think maths is not ________ science.A. so easy asB. less easyC. easierD. as easier as( ) 3. He _______ a glass of milk just now. He was very careless.A. knocked atB. knocked onC. knocked overD. knock off ( ) 4. Helen told me that she had some problems _______ his English learning.A. onB. forC. inD. with( ) 5. When she feels ________, I talk to her and make her happy.A. bored or unhappyB. boring or happyC. bored or happyD. boring or unhappy( ) 6. She looked ________ when she heard the good news.A. sadB. pleasantC. sadlyD. pleased( ) 7. Could you say ______ about it, please? I’d like to know _______.A. nothing else; moreB. anything else’ mostC. anything other; more C. something else; more( ) 8. She was late for the meeting yesterday __________ her car was broken on the way.A. because ofB. soC. becauseD. but( ) 9. What’s your brother like? ________.A. He’s fine, thank you.B. He’s doing his homework now.C. He’s tall and thin.D. He’s a famous doctor.( ) 10. I want to sing around the world _______.A. in the futureB. in a futureC. on futureD. on the future( ) 11. I’m thirsty now. Would you please give me _______ milk to drink?A. anyB. manyC. someD. a lots of( ) 12. I think picking apples ________ very interesting.A. areB. beC. amD. is( ) 13. Which word belongs to “Personality”?A. ponytailB. generousC. handsomeD. good-looking ( ) 14. I shall _______ Sandy because I think she’s the better girl of the two.A. keep away fromB. talk toC. vote forD. think of( ) 15. Betty is _______careful as I, but I’m _____ than you.A. as; much carefulB. so; more carefulC. as; much more carefulD. so; very careful三、根据句意用括号内所给单词的适当形式填(10分)1.May is a ________ (truly) friend.2. It’s important that my best friend doesn’t tell others my ________ (secret).3. She is ______________ (tall) girl in my class.4. I think swimming is not as ________ (interesting) as hiking.5. Lily’s drawing is ________ than Lucy’s. (bad)6. I think it’s time for ________ (we) to leave now.7. Who was the ________ in the high jump? (win)8. Han Meimei can learn Japanese by ________. (she )9. What about ________ shopping ? (go)10. Sandy’s drawing is ________ (beautiful) in the drawing competition四、根据句意,用所给动词的适当形式填空,必要时可加助动词。
Unit1 2021-2022学年 英语八年级上册牛津译林版8A U1 单元提优练习(二) - 答案
牛津译林版8A U1 单元提优练习(二)答案卷一、词汇运用1.—Do you know the height (high) of Yao Ming?—I don't know. But someone else is taller than him in the world.2. Mr. Black seems to be a friendly person because he has a smiling (smile) face.3. Andy, you are no longer a child. You should learn to look after yourself (you) well.4. Mo Yan's works (作品) of literature (文学) are very popular all over the world now.5. What's that boy with a square (方形的) face on your left in the photo like?6. The mother decides to be patient (耐心的) with her son next time.7. Many girls in my class have long straight (笔直的) hair.8. The bags over there are those singers’ (sing).9. It's important to make plans (计划) for our futures.10. It’ s not good to tell lies (谎言). You should be honest.二、动词填空1. Do you have any problems making (make) friends with your new classmates?2. Liu Xiang became a famous runner when he grew (grow) up.3. The Greens are planning (plan) to go on a trip to New Zealand right now.4. Mr. Xie told us that light travels (travel) much faster than sound.5. There isn’t going to be (not be) a fashion show next week, is there?6. Please tell the students not to skate (not skate) on the thin ice.7. We know the poor are (be) unlucky. We should try our best to help them.8. It is so cloudy. I think it is going to rain (rain).9. They hope their lunch will include (include) some vegetables.10. The heavy traffic makes them not get (not get) to the hall in time.三、单项选择( D ) 1. Cinderella wore a pair of crystal (水晶) shoes and became the girl at the party that night.A. prettyB. most prettyC. prettierD. prettiest( B ) 2. I think I have to call a taxi because the box is than I thought.A. heavyB. heavierC. the heavierD. the heaviest( C ) 3. Sam is a humorous person. We never feel with him.A. tiredB. tiringC. boredD. boring( D ) 4.—Do you have else to say for your mistake (错误)? —but sorry.A. anything: SomethingB. something; EverythingC. something; AnythingD. anything: Nothing ( C ) 5. Breakfast is meal of the day. It provides (提供) us with energy after a long night without food.A. importantB. more importantC. the most importantD. very important( B ) 6. It’s of the boy to share everything with us. We all like to make friends with him.A. politeB. generousC. honestD. clever( B ) 7. the small boy a round face like?A. How’s; withB. What’s; withC. How’s; haveD. What’s: have( B ) 8. Sandy is the most helpful girl in my class. She is ready to give a helping hand to anyone .A. all the timeB. any timeC. some timeD. some times( D ) 9. Is Zhujiang River the second river in our country.A. the largestB. largestC. the longestD. longest( C ) 10.—Who would you most like to talk your Future plans? —My best friend, of course.A. withB. about withC. with aboutD. of to( A ) 11.—Why do you think Sandy is ?—I always come to her when I am in trouble and need help.A. kind and helpfulB. kind and good-lookingC. clean and tidyD. clever and friendly ( B ) 12. carefully! Can you anything?A. Listen to; hearB. Listen; hearC. Hear; listen toD. Listen; listen to( A ) 13. The boy walked so fast that he the books the floor.A. knocked; ontoB. put; ontoC. knocked; downD. rushed; to( A ) 14.—For me, winter is the best season of a year!—Me too. if there’re some snows. I like a white world.A. BetterB. WorseC. LongerD. Shorter( C ) 15. of the twin brothers are polite. like them.A. Both; All weB. All; All of usC. Both; We allD. Each; All of us四、完成句子1. 你不可以告诉别人这件事。
北师大版2020八年级数学下册第四章因式分解单元过关测试题1(附答案)
北师大版2020八年级数学下册第四章因式分解单元过关测试题1(附答案) 1.下列各式从左到右的变形是因式分解的是( ) A .()a b c ab ac -=- B .()222312x x x -+=-+ C .()()2422x x x -=+-D .2(1)(2)32x x x x ++=++2.下列多项式中,可以提取公因式的是( ) A .ab +cd B .mn +m 2 C .x 2-y 2D .x 2+2xy +y 23.若m -n =-6,mn =7,则mn 2-m 2n 的值是( ) A .-13 B .13 C .42 D .-42 4.下列多项式中,不能因式分解的是( ) A .a 2+1B .a 2﹣6a+9C .a 2+5aD .a 2﹣15.下列等式从左到右的变形,属于因式分解的是 A .(a +b )(a ﹣b )=a 2﹣b 2 B .a 2+4a +1=a (a +4)+1 C .x 3﹣x =x (x +1)(x ﹣1)D .2111x x x x x ⎛⎫++=++⎪⎝⎭6.把多项式x 3-4x 因式分解所得的结果是( ) A .x (x 2-4)B .x (x +4)(x -4)C .x (x +2)(x -2)D .(x +2)(x -2)7.下列变形是因式分解是( ) A .211()x x x x+=+B .24(2)(2)am a a m m -=+-C .2221(2)(1)(1)a ab b a a b b b ++-=+++-D .2224(2)x x x ++=+ 8.下列各式中能用完全平方公式分解因式的是( ) A .22a ab b ++B .294y y -C .2414a a +-D .221q q +-9.已知a 、b 、c 是ABC V 的三条边,且满足22a bc b ac +=+,则ABC V 是( ) A .锐角三角形 B .钝角三角形 C .等腰三角形D .等边三角形10.已知a 、b 、c 是△ABC 的三边,且满足a 2﹣b 2+ac ﹣bc =0,则△ABC 的形状是( ). A .直角三角形 B .等边三角形 C .等腰三角形 D .无法确定 11.因式分解:a 2﹣b 2=_____.12.已知a 、b 满足2284200a b a b +--+=,则22a b -=________.13.分解因式0.81x 2-16y 2=(0.9x+4y )(__).14.因式分解:n (m ﹣n )(p ﹣q )﹣n (n ﹣m )(p ﹣q )=__. 15.分解因式:23a a +=_______________. 16.分解因式:2x 3﹣6x 2+4x =__________.17.把多项式m 2(a ﹣2)+m (2﹣a )分解因式等于_____. 18.把x 3y ﹣xy 3分解因式的结果是_____________________. 19.分解因式:b 2-9 =_____.20.分解因式:m 2n ﹣4mn ﹣4n=_____. 21.分解因式: (1)8a 3b 2+12ab 3c ; (2)(2x+y )2﹣(x+2y )2.22.分解因式: (1)a 3-a ;(2)8(x 2-2y 2)-x (7x +y )+xy .23.分解因式:(1)323a b 16a - (2)2x 2y-4xy+2y24.若正整数k 满足个位数字为1,其他数位上的数字均不为1且十位与百位上的数字相等,我们称这样的数k 为“言唯一数”,交换其首位与个位的数字得到一个新数k',并记F (k )=11127k k k k -'-'++. (1)最大的四位“言唯一数”是 ,最小的三位“言唯一数”是 ; (2)证明:对于任意的四位“言唯一数”m ,m+m'能被11整除;(3)设四位“言唯一数”n=1000x+100y +10y+1(2≤x≤9,0≤y≤9且y≠1,x 、y 均为整数),若F (n )仍然为“言唯一数”,求所有满足条件的四位“言唯一数”n .25.(1)计算:(a ﹣b )(a 2+ab+b 2)(2)利用所学知识以及(1)所得等式,分解因式:m 3﹣n 3﹣3mn (m ﹣n )26.已知x ≠1,计算: (1-x )(1+x )=1-x 2, (1-x )(1+x +x 2)=1-x 3, (1-x )(1+x +x 2+x 3)=1-x 4.(1)观察以上各式并猜想:(1-x )(1+x +x 2+…+x n )=________(n 为正整数). (2)根据你的猜想计算:①(1-2)×(1+2+22+23+24+25)=________; ②2+22+23+…+2n =________(n 为正整数); ③(x -1)(x 99+x 98+x 97+…+x 2+x +1)=________. (3)通过以上规律请你进行下面的探索: ①(a -b )(a +b )=________; ②(a -b )(a 2+ab +b 2)=________; ③(a -b )(a 3+a 2b +ab 2+b 3)=________.27.将一个三位正整数n 各数位上的数字重新排列(含n 本身)后,得到新的三位数abc (a <c ),在所有重新排列大的数中,当|a+c ﹣2b|最小时,我们称abc 是n 的“天时数”,并规定F (n )=b 2﹣ac .当|a+c ﹣2b|最大时,我们称abc 是n 的“地利数”,并规定G (n )=ac ﹣b 2.并规定M (n )=()()F nG n 是n 的“人和数”,例如:215可以重新排列为125,152,215,因为|1+5﹣2×2|=2,|1+2﹣2×5|=7,|2+5﹣2×1|=5,且2<5<7,所以125是215的“天时数”F (125)=22﹣1×5=﹣1,152是215的“地利数”,G (152)=1×2﹣52=﹣23,M (215)=112323-=-. (1)计算:F (168),G (168);(2)设三位自然数s=100x+50+y (1≤x≤9,1≤y≤9,且x ,y 均为正整数),交换其个位上的数字与百位上的数字得到t ,若s ﹣t=693,那么我们称s 为“厚积薄发数”;请求出所有“厚积薄发数”中M (s )的最大值. 28.把下列多项式因式分解 (l)x 3=4xy 2; (2)(a-1)(a+3)+4 29.把下列各式分解因式:(1)236x y xy - (2)2332525x y x y -(3)3241626m m m -+- (4)22(3)3a a --+(5)23()2()m x y y x --- (6)2318()12()b a b a b ---(7)1532223520x y x y x y +- (8)6x(x+y)-4y(x+y)(9)()()()a x a b a x c x a -+--- (10)()()()()m n p q m n p q ++-+- 30.(1)分解因式:(p+4)(p-1)-3p ; (2)化简:参考答案1.C【解析】试题解析:A. 右边不是整式积的形式,不是因式分解,故本选项错误;B. 右边不是整式积的形式,不是因式分解,故本选项错误;C. 是因式分解,故本选项正确;D. 右边不是整式积的形式,不是因式分解,故本选项错误;故选C.点睛:把一个多项式化为几个整式的积的形式,这种变形叫做把这个多项式因式分解. 2.B【解析】【分析】直接利用提取公因式法分解因式的步骤分析得出答案.【详解】解:A.ab+cd,没有公因式,故此选项错误;B.mn+m2=m(n+m),故此选项正确;C.x2﹣y2,没有公因式,故此选项错误;D.x2+2xy+y2,没有公因式,故此选项错误.故选B.【点睛】本题主要考查了提取公因式法分解因式,正确找出公因式是解题的关键.3.C【解析】【分析】首先把mn2+m2n分解因式,然后把已知等式代入其中即可求解.【详解】mn2+m2n=mn(n-m)=- mn(m-n),∵m-n=-6,mn=7,∴原式=6×7=42.故选:C.【点睛】此题考查了因式分解的应用,解题时首先通过因式分解把所求代数式变形,然后代入已知数据计算即可求解. 4.A 【解析】分析:利用因式分解的方法判断即可. 详解:A. 原式不能分解,符合题意; B. 原式2(3)a =-, 不合题意; C. 原式=x (x +5),不合题意; D. 原式(1)(1)a a =+-,不合题意, 故选A.点睛:考查因式分解的方法,常见的因式分解的方法有,提取公因式法,公式法,十字相乘法. 5.C 【解析】A. 是整式的乘法,故A 错误;B. 没把一个多项式转化成几个整式积的形式,故B 错误;C. 把一个多项式转化成几个整式积的形式,故C 正确;D. 没把一个多项式转化成几个整式积的形式,故D 错误; 故选:C. 6.C 【解析】试题解析:()()()324422.x x x x x x x -=-=+-故选C.点睛:先提取公因式,再用公式进行因式分解. 7.B 【解析】解:A .211()x x x x+=+ ,右边不是整式的乘积的形式,不是因式分解,故A 错误;B .24(2)(2)am a a m m -=+-,正确;C .2221(2)(1)(1)a ab b a a b b b ++-=+++-,右边不是整式的乘积的形式,不是因式分解,故C 错误;D .2224(2)x x x ++=+,左右两边不相等,不是恒等变形,故C 错误. 故选B . 8.C 【解析】A 选项中间乘积项不是两底数积的2倍,故本选项错误;B 选项不符合完成平方公式的特点,故本选项错误;C 选项符合完全平方公式的特点;D 选项不符合完成平方公式的特点,故本选项错误, 故选C . 9.C 【解析】 【分析】已知等式左边分解因式后,利用两数相乘积为0两因式中至少有一个为0得到a=b ,即可确定出三角形形状. 【详解】已知等式变形得:(a+b )(a-b )-c (a-b )=0,即(a-b )(a+b-c )=0, ∵a+b-c≠0, ∴a-b=0,即a=b , 则△ABC 为等腰三角形. 故选C . 【点睛】此题考查了因式分解的应用,熟练掌握因式分解的方法是解本题的关键. 10.C【解析】a 2−b 2+ac−bc=0, 由平方差公式得: (a+b)(a−b)+c(a−b)=0, (a−b)(a+b+c)=0,∵a 、b 、c 三边是三角形的边, ∴a 、b 、c 都大于0, ∴本方程解为a=b , ∴△ABC 一定是等腰三角形. 故选:C.11.(a+b )(a ﹣b ) 【解析】试题分析:直接应用平方差公式即可:()()22a b a b a b -=+-.12.12 【解析】分析:先根据完全平方公式的特征对等式2284200a b a b +--+=的左边进行因式分解可得:()()22420a b -+-=,再根据非负数的非负性可得:4,2a b ==,然后代入求解即可. 详解:因为2284200a b a b +--+=,所以22816440a a b b -++-+=, 所以()()22420a b -+-=, 所以()()2240,20a b -=-=, 所以4,2a b ==,所以2216412a b -=-=.点睛:本题主要考查利用完全平方公式进行因式分解,解决本题的关键是要熟练掌握利用完全平方公式进行因式分解. 13.0.9x -4y 【解析】试题分析:本题利用的是平方差公式进行因式分解,则原式=()()()()220.940.9x 4y 0.9x 4y x y -=+-. 14.2n (m ﹣n )(p ﹣q ).【解析】解:原式=n (m ﹣n )(p ﹣q )+n (m ﹣n )(p ﹣q )=2n (m ﹣n )(p ﹣q ).故答案为:2n (m ﹣n )(p ﹣q ). 15.(3)a a + 【解析】试题解析:23a a +=a(a+3). 16.2x (x ﹣1)(x ﹣2). 【解析】分析:首先提取公因式2x ,再利用十字相乘法分解因式得出答案. 详解:2x 3﹣6x 2+4x =2x (x 2﹣3x+2) =2x (x ﹣1)(x ﹣2). 故答案为2x (x ﹣1)(x ﹣2).点睛:此题主要考查了提取公因式法以及十字相乘法分解因式,正确分解常数项是解题关键. 17.:m (a ﹣2)(m ﹣1) 【解析】m 2(a ﹣2)+m (2﹣a )=m 2(a ﹣2)﹣m (a ﹣2)=m (a ﹣2)(m ﹣1). 故答案为m (a ﹣2)(m ﹣1). 18.xy (x +y )(x ﹣y ) 【解析】 【分析】先提公因式3x ,再利用平方差公式分解因式. 【详解】 解:故答案是:【点睛】本题主要利用提公因式法、完全平方公式分解因式,熟记公式结构特点是解题的关键. 19.(b+3)(b-3) 【解析】原式=(3)(3)b b +-. 故答案为:(3)(3)b b +-. 20.n (m 2﹣4m ﹣4) 【解析】 试题解析:244,m n mn n --()244n m m =--.故答案为:()244n m m --.21.(1)4ab 2(2a 2+3bc );(2)3(x+y )(x ﹣y ). 【解析】 【分析】(1)直接提取公因式4ab 2,进而分解因式即可; (2)直接利用平方差公式分解因式得出答案. 【详解】解:(1)8a 3b 2+12ab 3c =4ab 2(2a 2+3bc ); (2)(2x+y )2-(x+2y )2 =(2x+y+x+2y )(2x+y-x-2y ) =3(x+y )(x-y ).22.(1)a (a -1)(a +1);(2)(x +4y )(x -4y ).【解析】试题分析:(1)首先提取公因式,进而利用平方差公式分解因式即可; (2)首先去括号,进而合并同类项,再利用平方差公式分解因式即可. 试题解析:解:(1)原式=a (a 2-1)=a (a -1)(a +1).(2)原式=8x 2-16y 2-7x 2-xy +xy =x 2-16y 2=(x +4y )(x -4y ). 23.(1)a 3(b+4)(b-4) (2)2y 2(1)x - 【解析】试题分析:(1)(2)利用提取公因式和公式法因式分解.试题解析:(1)3233216(16a b a a b -=-)=a 3(b +4)(b -4) .(2)2x 2y -4xy +2y =2y (x 2-2x +1)=2y (x-1)2.24.(1)9991;221;(2)详见解析;(3)满足条件的所有的四位“言唯一数”为3221和8551【解析】【分析】根据题目给出的新定义,正整数k 满足个位数字为1,其他数位上的数字均不为1且十位与百位上的数字相等,称这样的数k 为“言唯一数”,解答即可.【详解】(1)最大的四位“言唯一数”是 9991 ,最小的三位“言唯一数”是 221 ;(2)证明:设1000100101m a b b =+++,则'100010010m b b a =+++()'1001220100111912091m m a b a b ∴+=++=++,a b Q 都为正整数,则912091a b ++也是正整数∴对于任意的四位“言唯一数”m ,'m m +能被11整除.(3) Q 1000100101n x y y =+++(29x ≤≤,09y ≤≤且1y ≠,x 、y 均为整数) '1000110n y x ∴=++.则()()11912091''9999991111271127x y n n n n x F n +++--=-+=-+ 91109137371x y x =++-++5420129x y =++()F n Q 仍然为言唯一数, 20y 末尾数字为0,129末尾数字为9则54x 的末尾数字为2,3x ∴=或8x =①当3x =时,542012920291x y y ++=+,2y =时,()331F n =,此时3221n =②当8x =时,542012920561x y y ++=+,5y =时,()661F n =,此时8551n =满足条件的所有的四位“言唯一数”为3221和8551【点睛】本题主要考查了对因式分解的应用,对新定义的理解程度时解答本题的关键.25.(1)a3﹣b3;(2)(m﹣n)3.【解析】【分析】(1)根据多项式乘以多项式的法则进行计算即可;(2)利用分组分解法,先将前两项分为一组,根据(1)的立方差公式分解因式,再提公因式即可.【详解】解:(1)原式=a3+a2b+ab2﹣a2b﹣ab2﹣b3=a3﹣b3;(2)原式=(m﹣n)(m2+mn+n2)﹣3mn(m﹣n)=(m﹣n)(m2﹣2mn+n2)=(m﹣n)3【点睛】本题考查了多项式乘以多项式和因式分解,熟练掌握立方差公式是关键.26.(1)①-63;②2n+1-2;③x100-1.(2)①a2-b2;②a3-b3;③a4-b4【解析】试题分析:(1)根据题意易得(1-x)(1+x+x2+…+x n)=1-x n+1;利用猜想的结论得到①(1-2)(1+2+22+23+24+25)=1-26=1-64=-63;②先变形2+22+23+24+…+2n=2(1+2+22+23+24+…+2n-1)=-2(1-2)(1+2+22+23+24+…+2n-1),然后利用上述结论写出结果;③先变形得到(x-1)(x99+x98+x97+…+x2+x+1)=-(1-x)(1+x+x2+…+x99),然后利用上述结论写出结果;(2)根据规律易得①(a-b)(a+b)=a2-b2;②(a-b)(a2+ab+b2)=a3-b3;③(a-b)(a3+a2b+ab2+b3)=a4-b4.试题解析:(1)由题意知(1−x)(1+x+x2+…+x n)=1−x n+1;所以①(1−2)(1+2+22+23+24+25)=1−26=1−64=−63;②2+22+23+24+…+2n=2(1+2+22+23+24+…+2n−1)=−2(1−2)(1+2+22+23+24+…+2n−1)=−2(1−2n)=2n+1−2;③(x−1)(x99+x98+x97+…+x2+x+1)=−(1−x)(1+x+x2+…+x99)=−(1−x100)=x100−1,(3)①(a−b)(a+b)=a2−b2;②(a−b)(a2+ab+b2)=a3−b3;③(a−b)(a3+a2b+ab2+b3)=a4−b4.故答案为:(1)①-63;②2n+1-2;③x100-1.(2)①a2-b2;②a3-b3;③a4-b4点睛:此题考查了平方差公式,规律型:数字的变化类以及多项式乘多项式,熟练掌握运算法则及公式是解本题的关键.27.(1)28,47;(2)17 39【解析】【分析】(1)将168重新排列为168、186,618,计算出|1+8﹣2×6|=3、|1+6﹣2×8|=98+6﹣2×1|=12,且3<9<12,可得168的天时数与地利数,再根据天时数和地利数的定义计算可得;(2)由s=100x+50+y,t=100y+50+x,根据s﹣t=693可得81xy=⎧⎨=⎩或92xy=⎧⎨=⎩,据此得出s的“厚积薄发数”为851或952,再分别求出这两个数的“人和数”,比较大小即可得.【详解】(1)168重新排列为168、186、618.∵|1+8﹣2×6|=3、|1+6﹣2×8|=9、|8+6﹣2×1|=12,且3<9<12,∴168是168的天时数,F (168)=62﹣1×8=28;618是168的地利数,G(618)=6×8﹣12=47.(2)s=100x+50+y,t=100y+50+x.∵s﹣t=99x﹣99y=693,∴99(x﹣y)=693,x﹣y=7,x=y+7,∴1≤x≤9,1≤y≤9,∴1≤y+7≤9,∴1≤y≤2,∴81xy=⎧⎨=⎩或92xy=⎧⎨=⎩,∴s的“厚积薄发数”为851或952,当s=851时,可以重新排列为158,185,518.∵|1+8﹣2×5|=1,|1+5﹣2×8|=10,|5+8﹣2×1|=11,∴158为851的“天时数”,F(851)=52﹣1×8=17;518为851的“地利数”G(851)=5×8﹣12=39;则M (851)=1739; 当s =952时,可以重新排列为529、295、259.∵|5+9﹣2×2|=10,|2+5﹣2×9|=11,|2+9﹣2×5|=1,∴259为952的“天时数”,F (952)=52﹣2×9=7; 295为952的“地利数”,G (952)=2×5﹣92=﹣71,则M (952)=﹣771; 综上,知所有“厚积薄发数”中M (s )的最大值为1739. 【点睛】本题考查了因式分解的应用,解题的关键是理解题意,灵活运用所学知识解决问题,解题的突破点是学会应用枚举法求出满足条件的天时数、地利数及人和数. 28.(1)()() x x 2y x 2y +- ;(2) ()2a 1+ 【解析】试题分析:(1)先提取公因式,然后再利用平方差公式进行分解即可;(2)先进行乘法运算,合并同类项后利用完全平方公式进行分解即可.试题解析:(1)()3222x 4xy x x 4y-=- ()()x x 2y x 2y =+- ; (2)()()2a 1a 34a 2a 34-++=+-+ 2a 2a 1=++ ()2a 1=+.29.(1)3xy(x-2); (2)225(5)x y y x -; (3)22(2813m m m --+); (4)3)(27)a a --(; (5)()(322)x y m x y --+; (6)26()(52a b b a --);(7) 225314)x y xy y +-(; (8)2(x+y)(3x-2y); (9)()()x a a b c ---; (10)2()q m n +.【解析】试题分析:都利用提公因式法分解因式即可.试题解析:(1)原式=3xy(x-2);(2)原式=()2255x y y x -;(3)原式=22(2813m m m --+);(4)()3)27a a =--原式(;(5)原式=()()322x y m x y --+;(6)原式=()26(52a b b a --);(7)原式= 225314)x y xy y +-(;(8)原式=2(x+y)(3x-2y);(9)原式=()()x a a b c ---;(10)原式=()2q m n +.30.(1)原式=p+2)(p-2);(2)原式=a+6.【解析】试题分析:(1)先计算多项式乘多项式,将原式转化为多项式的形式,然后利用平方差公式进行分解即可;(2)先利用完全平方公式计算乘方,然后计算单项式乘多项式和多项式除单项式,最后合并同类项即可.试题解析:解:(1)原式=p 2+3p -4-3p=p 2-4=(p +2)(p -2);(2)原式=a 2 +4a +4-a 2-2a -a +2=a +6.。
新译林8A英语UNIT1单元知识点归纳及练习题含答案
新译林8A英语UNIT 1单元知识点归纳及练习题8A Unit 1 Friends一、词汇大集合1. keep a secret 保守秘密2. care about 关心、关怀3. tell a lie (to sb.) (对某人)说谎4. lie –lied –lied 说谎lie –lay –lain 躺5. play a joke on sb. 跟某人开玩笑6. tell sb. funny jokes 给某人讲可笑的笑话7. be willing to do sth. 愿意做某事、乐意做某事be ready to do sth. 乐意做某事、准备好做某事8. have a good sense of humour 有很好的幽默感= be (very) humorous9. in height 在高度方面10. in weight 在体重方面11.patient --- impatient12.in a low voice 低声地13. buy two more books= buy another two books 再买两本书14.eat one more apple= eat another apple 再吃一个苹果15.share sth. with sb. 跟某人分享某物16. qualities of a good friend 好朋友的品质17. tell him everything about yourself 告诉他有关你的一切18. share my joy(不可数) / sadness分享我的快乐/悲伤19.have problems with sth. 在某方面有问题20.have problems doing sth. 做某事有问题21. believe what he says (said)=believe his words 相信他的话22.trust sb. 信任某人23.agree to do sth. 同意做某事24.agree with sb. 同意某人的观点25.one of my best friends 我最好的朋友这一26.one of the longest rivers 最长的河流之一27.one of the most famous film stars最著名的影星之一28.be generous / kind to sb. 对某人慷慨/友善29.be ready to help people any time在任何时候乐意帮助人30.help me with my homework在家庭作业方面帮助我31.give a seat on the bus to someone in need 在公交车上让座给有需要的人32.have a good/sweet voice 有个好/甜美的嗓音33.wear small round glasses 戴小小的圆框眼镜34.make him look smart 使他看起来精干35. never feel bored with him 和他一起从不感到无聊36. a boring film 一部无聊的电影37. make me thirsty 使我口渴make sb. / sth.+adj.make me laugh使我大笑make sb. do sth.38. walk past our desks=pass our desks 从我们桌子旁边经过39. knock ...onto the ground 把…撞到地上knock over 撞翻,碰倒knock …off…把…从…上撞下来40.so interesting 如此有趣41. have big bright eyes 有双明亮的大眼睛42. have/wear long straight hair留长直头发43. say a bad word about sb.=say bad things about sb. 说某人的坏话44. a true friend 一个真诚的朋友45.sth. worry sb. 某事困扰某人46.sb. be worried about sth. 某人担心某事47.choose sb. as /(to be) your best friend 选择某人作为你最好的朋友48. look smart in his small round glasses 戴着他的小圆框眼镜看起来帅49.listen to people carefully 认真听人们倾诉50.help people with their problems帮人们解决问题51.make friends with sb. 跟某人交朋友52. among the six students 在六名学生当中53. among all the Chinese artists 在所有的中国艺术家当中54. talk about our future plans谈论我们的未来计划55.a small girl with a ponytail一个扎马尾辫的女孩55.a boy with / wearing glasses一个戴着眼镜的男孩56.both……and….. 既…又….57.be/ make / become an excellent teacher 成为一名优秀的教师58. feel bored or unhappy 感觉无聊或不开心59.like her bright smiling eyes 喜欢她明亮略带微笑的眼睛60.wear/have a smile on one’s face 面带微笑二、句型大集合1.Can I have something to drink? 我能要点喝的吗?2.Can I have some more food? 我可以再要一些食物吗?3.There is nothing in the fridge. 冰箱里什么也没有。
牛津译林版8A期中1-4单元基础知识复习(翻译)含答案
Unit l Friends1.张老师关心每个学生,就像他们的父亲一样。
2.据说他们的语文老师擅长在课堂上讲滑稽的笑话。
3.你觉得是什么使得英语课这么有趣呢?4.替朋友保守秘密是好朋友最重要的品质之一。
5.李平是个诚实的男孩,他从不撒谎。
6.她长长的直发使她很特别。
7.如果你工作有困难,我愿意任何时候帮助你。
8.由于在床上看书时间太多,他视力很差。
9.Betty从不感到无聊或不愉快,她常开些有趣的玩笑,逗我笑。
10.他很和善,从不说别人的坏话。
11.当我读到你的作文时,我想起了名叫May的好友。
12.昨天当我听到这首歌的时候,我想起了我的一个老朋友。
13.昨天在公交车上,我把座位让给了一个抱婴儿的妇女。
14.如果你需要帮助,你可以在任何时间给我打电话。
15.长大后我想当一位艺术家。
16.安迪是我最好的朋友,我愿意告诉他任何事情。
17.当夏天来到时,天气变得越来越热。
18.他认为骑自行车是最利于健康的户外活动之一。
19.第九题比第十二题难多了。
20.在考试中你越细心,犯的错误就越少。
21.野营没有滑水危险。
22.当我们拥有足够的时间时,我们就去周游世界。
23.午餐期间她总是一个人坐在操场上。
24.我在那儿时交了许多朋友。
25.李强将来想成为一名社会工作者。
26.王叔叔经常帮助人们解决他们的问题。
27.昨天我的父母和我谈论了关于他们的未来计划。
参考答案:1.Mr.Zhang cares about every student,just like their father.2.It is said that their Chinese teacher is good at telling funny jokes in class.3.What do you think makes English classes so interesting?4.Keeping a secret for friends is one of the most important qualities of a good friend.5.Li Ping is an honest boy and he never tells lies.6. Her long straight hair makes her very special .7. If you have problems with your work, I am willing to help you any time.8. He has poor eyesight because of reading in bed too much time.9. Betty never feels bored or unhappy.She often tells funny jokes and makes me laugh.10. He's very kind and never says a bad word about others.11. I thought of my good friend named May when I read about your composition.12.I thought of an old friend of mine when I heard the song yesterday.13 .Yesterday I gave my seat to a woman with a baby on the bus.14.You can call me any time if you need help.15.I’want to be an artist when I grow up.16.Andy is my best friend.I am willing to tell him anything.17. When summer comes, the weather becomes hotter and hotter.18. He thinks cycling is one of the healthiest outdoor activities.19. The ninth problem is much more difficult than the twelfth one.20. The more careful you are in an exam, the fewer mistakes you'll make.21. Camping is not as dangerous as skating.22.When we have enough time,we will travel around the world.23.During lunchtime, she always sit alone in the playground.24.He made many friends while he was there.25.Li Qiang would like to be a social worker in the future.26.Uncle Wang often helps people with their problems.27.Yesterday my parents talked about their future plans with me.8A Unit2 School life 1.英特网上的广告比电视上少。
度八年级上英语8A Unit1-2单元测试卷有答案
8A Units 1-2单元试卷班级_________姓名_________学号_______得分_________一.选择填空15分()1. There is _______ in the fridge.A. else somethingB. nothing elseC. not elseD. else nothing()2. My father‟s new hair style makes ________.A. him to look youngB. him youngC. him looks youngD. him looking young()3. David is taller than _____ in his class.A. other studentB. the other studentC. other studentsD. the other students()4. My English teacher often looks _______. She is looking _______ at us now.A. happy, happyB. happily, happyC. happily, happilyD. happy, happily()5. Wang H ai‟s painting is______ i n the Art Competition.A. more beautifulB. most beautifulC. the most beautifulD. beautiful()6. What‟s your best friend like?--- _________.A. He is an officer.B. He is fine. Thank you.C. He likes playing computer games.D. He is friendly and helpful.()7.…My Heart Will Go On‟ was one of _______ songs of 1998.A. popularestB. more popularC. veryD. the most popular()8. John has three sisters. Mary is the _____ of the three.A . most cleverest B. more clever C. cleverest D. cleverer()9. If we followed the plan, we could do the work better with ___ money and ____ people.A. little, fewerB. fewer, lessC. less, fewerD. less, few()10. Of the two shirts, I‟d like to choose _____ one.A. the less expensiveB. the most expensiveC .less expensive D. most expensive()11. _____ you work, _____ result you will get.A. The harder, the betterB. the more hard, the more betterC. The harder, a betterD. more hard, more better()12.The country park is_______interesting than any other park in our city.It has _______visitors than any other park.A.much; muchB. many; manyC. more; moreD. more; many() 13. My friend loves playing softball. She _____ two hours ______ every day.A. spends, practising playingB. spends, practising playC. spend, to practise playingD. spending, practise playing() 14.People in the UK say “autumn” while people in the USA say “”.A. fallB. hallC. yardD. vacation() 15.In my ideal school, we have a big library _____ lots of _____books.A. has, useB. has, usefulC. with, uselessD. with, useful二.完型填空10分Making friends is not easy. Sometimes it can take ___1____ before you become true friends with someone.There are some common qualities of a…TRUE FRIEND‟.Firstly,true friends should be _____2___. Being honest means _____3___ telling lies, but of course this is not always so easy.Sometimes you do not want your friends to know____4____about you,such as you getting a terrible score in a test.Then you might want to tell a lie to make yourself feel much ___5___, but this is not a good idea. Your friends will find out the truth sooner or later, and they will be ___6___because you lied to them. The second most important quality of a true friend is being a good ___7__. You do not want to have a friend who is ___8___ to listen to your problems, or a friend who might talk about your problems with everybody in school. It is very important for friends to trust each other. Finally, be generous to your friends. You should ___9___ your things with your friends.Please remember ____10___ we give you. We believe you will have more friends in the future.1. A. minutes B. days C. weeks D. years2. A. kind B. honest C. helpful D. polite3. A. never B. always C. sometimes D. usually4. A. something good B. anything goodC. something badD. anything bad5. A. better B. worse C. bad D. good6. A. nervous B. happy C. angry D. cheerful7. A. listener B. talker C. speaker D. reader8. A. willing B. ready C. not willing D. getting ready9. A. give B. send C. talk D. share10.A. the jokes B. the advice C. the secrets D. the activities三.阅读理解10分( A )Many teenagers feel that the most important people in their lives are their friends. They believe that their family members don‟t know as well as the ir friends do .In large families , it is quite often for brothers and sisters to fight with each other and then they can only go to their friendsfor some ideas .It is very important for teenagers to have some good friends .Even when they are not with their friends,they usually spend a lot of time talking among themselves on the phone .This communication(交际)is very important in children‟s growing up,because friends can discuss something . These things are difficult to say to their family members .However,parents often try to choose their children‟s friends for them .Some parents may even stop their children from meeting their friends .Have you ever thought of the following questions ?Who choose your friends ?Do you choose your friends or your friends choose you ?Have you got a good friend your parents don‟t lik e? Your answers are welcome .()1. Many teenagers think that__________ can understand them better .A.friendsB. brothersC. sistersD. parents()2. ________is very important to teenagers .A. To make friendsB. CommunicationC. To stop meeting friendsD. Both A and B()3. When teenagers have something difficult to say to their parents, they usually __________.A. stay alone at homeB. fight with their friendsC. discuss it with their friendsD. go to their brothers or sisters for help() 4. The sentence“ Your answers are welcome . ”means“ __________” .A. You are welcome to discuss the questions with usB. We have no idea , so your answers are welcomeC. Your answers are always rightD. You can give us all the right answers() 5. Which of the following is the writer‟s attitude (态度) ?A. Parents should choose friends for their children.B. Children should choose everything they like.C. Parents should understand their children.D. Teenagers should only go to their friends for help.( B )American and British people both speak English of course. But sometimes there are some important differences between British English and American English.First of all, they sound very different. Often, Americans don‟t say each word separately. They say words together.Americans may say“I dunno”instead of“I don‟t know”.Or they may say “Whaddya say?”instead of“What did you say?”However,the British are more careful.They usually say all the words and keep them separate.Sound is not only the difference. Words sometimes have different meanings too. For example, the vocabulary for cars and driving is very different. Americans drive trucks, but in England people drive lorries.Many expressions(短语)are also different in the two countries. In England, if you are going to telephone your friends, you “phone them up”. In America, you “give them a call”. When you are saying goodbye in England you might say “Cheerio!” In America you might say “See you later.”There‟re also some differences in grammar. For example, Americans usually use the helping verb “do” when they ask a question. They say “Do you have a storybook?” But the British oftenleave out the helping verb. They say “Have you a storybook?”Most languages are like nguages change over time.When people live in separate places, the languages change in different ways. This is what has happened to English. It can also happen to other languages, such as French. Many people in Canada speak French but their French is very different from the French of France.() 1. What does the word “separately” mean in this passage? It means “_____”.A.含糊地B.快速地C.分开地D.简略地() 2. The vocabulary for cars and driving is _____.A. an example of British EnglishB. an example of American EnglishC. the same in America and EnglandD. not the same in America and England() 3. Languages _____.A. are always changing as time passesB. keep unchanged even if time changesC. are the same in all placesD. are easy to learn() 4. Which of the following sentences is right according to the passage?A. American people usually say“ I don‟t know” instead of“ I dunno”.B. There are four differences between American and British English.C. Canadians speak all the same French as Frenchmen.D. When people live in different places, the language are spoken in the same way.() 5. This passage is mainly about _____.A. English vocabularyB. how American sounds are different from British soundsC. the way the British say wordsD. some differences between American and British English四.词汇15分A.根据所给的提示意思完成句子1. His s___________ eyes show that he likes the present very much.2. This is one of the most interesting _________ (杂志) in the library.3. He is an honest boy .We can ___________(相信)what he says .4. How many___________(英雄) do you know from the story5. Do you like ____________ (英国的) English or American English?B.用所给词的适当形式填空1.Who is __________( slim ) ,Betty, May or Millie ?2. He felt ___________(happy) because he lost his wallet on his way home.3.What‟s your ____________(weigh)? ---Sorry, I don‟t know .4.Now it is time for the ___________( week ) report.5. She wants to be a singer as __________(famous) as Celine Dion.C.用所给词或词组的适当形式填空in Grade 8 a mixed school wear school uniforms be likehave less free time the Reading Week Computer StudiesMy name is Tom. I study in Beijing Sunshine Secondary School. It s _1_______________. My favourite subject is_2_______________because I like working on the computer.I study more subjects and _3_________________ than my British friend John. My school _4_______________ John s school. We 5____________________and do morning exercises. I like my school.五.句型转换10分1.Lucy was born in 1998. Lily was born in 1998.(改为同义句)Lucy ____________________________ Lily.2.Sandy wants to be a singer when she grows up.(对划线部分提问)______________ Sandy _____________________when she grows up?3.English is the most interesting subject.(改为同义句)English is ___________________________________ subject.4.Nobody else is cleverer than Daniel in his class.(改为同义句)Daniel is ______________ student in his class.5.I don t know how I can work out this problem.(改为同义句)I don t know ______________ _________ out this problem.六.翻译下列句子10分1.不要在课上和我讲话,下课后我会和你讨论。
人教版新目标英语八年级下短文填空10篇(含答案)[1]
人教版新目标英语八年级下短文填空10篇(含答案)(word版可编辑修改) 编辑整理:尊敬的读者朋友们:这里是精品文档编辑中心,本文档内容是由我和我的同事精心编辑整理后发布的,发布之前我们对文中内容进行仔细校对,但是难免会有疏漏的地方,但是任然希望(人教版新目标英语八年级下短文填空10篇(含答案)(word版可编辑修改))的内容能够给您的工作和学习带来便利。
同时也真诚的希望收到您的建议和反馈,这将是我们进步的源泉,前进的动力。
本文可编辑可修改,如果觉得对您有帮助请收藏以便随时查阅,最后祝您生活愉快业绩进步,以下为人教版新目标英语八年级下短文填空10篇(含答案)(word版可编辑修改)的全部内容。
Passage OneA taxi hit a truck. A policeman spoke to the taxi driver and to the 1 drvier。
He also spoke to Tom. He was a witness(证人). This is what they said。
TRUCK DRIVER : I was 2 from the airport to Newton。
A car crossed the road, so I slowed down (减速)。
I didn't stop。
A taxi hit the back of my truck。
Nobody was seriously 3 but both cars were damaged(损毁的).TAXI DRIVER: I was driving behind a truck a few kilometers from Newton. The truck stopped 4 。
The driver didn’t give me a warning(警示), I was driving very slowly. I could not pass the truck because 5 were two cars coming near from Newton. My taxi hit the truck, and some glass 6 my left hand。
8A_Unit_4_Wild_animals教学案及答案(1)
8A Unit4参考答案8A Unit4 Wild animals Comic strip & Welcome to the unit一1.look happy 2. wild animals 3.talk with them 4.favourite 5.look after yourself 6.处于危险中7.大熊猫8. 没有人二1.delicious 2.bear kangaroo tiger 3.die 4. wild smaller三1.The food looks delicious.2. No one is waiting for me at school gate.3.How much do you know about wild animals?4. If it rains tomorrow, I won’t go to Beijing zoo.5. If I die, no one will look after you.Unit 4 Wild animals Reading(1)一1. for the first time 2.eight years later 3.not any more 4.encourage sb.to do sth.5.grow into 6.look after oneself 7.have nowhere to live 8.have baby 9.oneself10 In the future二1. sad 2. weighed 3. shoots leaves 4.called 5. encourage to brave6. danger7. will stay8.not to kill三.1.on his own 2. There will not be any bears soon if we do not protect them.3.How much did weigh4.wolves protect their baby.8A Unit4 Wild animals Reading (2)一1. start 2. looks like 3. weighed 4. beginning二1.when was old 2. for the first time 3.How much weigh4.no more 5.for 6. on his own 三.1.If we do nothing , soon there will be no giant pandas in the world.2.At the beginning ,Xiwang drank her mother’s milk for up to 14 hours a day .3.If people find baby pandas alone, they will often take them away.8A Unit4 Wild animals V ocabulary(略)8A Unit 4 Wild animals Grammar A一1. will be 改成am 2.去掉,3.去掉a 4. will be二1.w ill attack 2. passes will feel 3. hunted 4.made 5. male三.1. If the wolf is hungry, what will it do?2. If the tiger has a baby, they will live in groups together.3. If the elephants are thirsty ,they will find water.4.If you arrive at noon,you will see me .5.If I see a snake in front of me , I will run the other way.8A Unit 4 Wild animals Grammar B一.1. because 2. so 3. because 4. because of 5. because二.1. I hate it so I never eat fish .2. Why did all the people cheer?3. because of her4. The girl ran away quickly because she felt frightened.三. 1.Xiwang had to look after herself because her mother had another baby.2. I went to Beijing Zoo because I wanted to watch the wild animals.3. We must protect small animals because we are friends!4. If there is no water and air , there will be no life on the earth . So we should protect the environment8A Unit 4 Wild animals Integrated skills A一.1.liveas a family 2. loss of living areas 3. make medicine from … 4.the clothes made of animals fur 5. make a lot of money 6. elep hants’tusks 7.suitable homes 8.look lovely on me二.1. leaves 2.sadly 3. elephants’ 4.feeding 5.ninth 6.following 7.peaceful8 mice 9. loss三 1.sad for forests 2.don’t protect will have nowhere to live 3.following actions to4.dolphin zebra show5. character take action6. snake be frightened8A Unit 4 Wild animals Integrated skills B & Pronunciation一1.train 2.sold 3. farmland 4.loss 5. smell 6.characters 7.insect 8.peaceful 9.suitable 10 medicine三.1.The clothe looks lovely on me .2.I f I don’t buy it, someone else will buy it.3.People won’t kill wild animals any more .4.Maybe you are right .5.If we continue to cut down the forests, many animals will have nowhere to live.8A Unit 4 Wild animals Main task一1. are becoming farmlands 2. spends up to 12 hours 3.keep taking the land have nowhere to live 4 looks like 5.for their fur and bones二1.去掉前will 2. That – it 3.look after herself 4. uprightly—upright5.are – is三略8A Unit 4 Wild animals Checkout一.bbbbcba二.1.at birth 2.don’t anywhere 3 How weight 4.What do 5.no more。
2021-2022学年浙教版八年级数学下册《第1章二次根式》单元综合练习题(附答案)
2021-2022学年浙教版八年级数学下册《第1章二次根式》单元综合练习题(附答案)1.等式=(b﹣a)成立的条件是()A.a≥b,x≥0B.a≥b,x≤0C.a≤b,x≥0D.a≤b,x≤0 2.如果m=﹣2,n=+2,那么m和n的关系是()A.互为相反数B.互为倒数C.相等D.互为负倒数3.已知x=﹣2,x4+8x3+16x2的值为()A.B.C.3D.94.若a=2﹣,则代数式2a2﹣8a﹣1的值等()A.1B.﹣1C.4+4D.﹣25.把四张形状大小完全相同的小长方形卡片(如图①)不重叠地放在一个底面为长方形(长为cm,宽为4cm)的盒子底部(如图②),盒子底面未被卡片覆盖的部分用阴影表示.则图②中两块阴影部分的周长和是()A.4cm B.16cm C.2(+4)cm D.4(﹣4)cm 6.在化简时,甲、乙两位同学的解答如下,那么两人的解法()甲:===乙:===A.两人解法都对B.甲错乙对C.甲对乙错D.两人都错7.使等式=成立的正整数对(x,y)的个数是()A.1B.2C.3D.48.若x是整数,且•有意义,则•的值是()A.0或1B.±1C.1或2D.±29.已知方程+3=,则此方程的正整数解的组数是()A.1B.2C.3D.410.(易错题)已知x+=,则x﹣的值是()A.B.﹣C.±D.不能确定11.若二次根式是最简二次根式,则最小的正整数a为.12.若ab>0,a+b<0.那么下面各式:①=•;②•=1;③÷=﹣b;④•=a,其中正确的是(填序号)13.在,,,……,2023这2023个式子中,与2205可以合并的共有个14.若x=﹣1,则x3+x2﹣3x+2021的值为.15.已知a,b都是实数,b=+,则a b的值为.16.当x=时,有最小值.17.已知+2=b+8,则的值是.18.若=﹣a,则a应满足的条件是.19.化简:=.20.已知x,y均为实数,且满足=(y﹣1),那么x2023﹣y2023=.21.已知实数a满足|2012﹣a|+=a,则a﹣20122=.22.计算:(1)比较﹣和﹣的大小;(2)求y=﹣+3的最大值.23.化简:.24.(1)一个正数的平方根是2a﹣3与5﹣a,求这个正数.(2)已知x、y都是实数,且,求y x的值.25.求=中的x.参考答案1.解:根据算术平方根的意义可知,b﹣a≥0且x≥0,即a≤b,x≥0.故选:C.2.解:m+n=﹣2=2,mn=,∴m和n互为倒数,故选:B.3.解:∵x=﹣2,∴x2=(﹣2)2=()2﹣2××2+22=7﹣4+4=11﹣4,则原式=x2(x2+8x+16)=x2(x+4)2=(11﹣4)(﹣2+4)2=(11﹣4)(2+)2=(11﹣4)(11+4)=112﹣(4)2=121﹣112=9,故选:D.4.解:∵a=2﹣,∴2a2﹣8a﹣1=2(a﹣2)2﹣9=2(2﹣﹣2)2﹣9=2×5﹣9=1.故选:A.5.解:设小长方形卡片的长为x,宽为y,根据题意得:x+2y=,则图②中两块阴影部分周长和是2+2(4﹣2y)+2(4﹣x)=2+4×4﹣4y﹣2x=2+16﹣2(x+2y)=2+16﹣2=16(cm).故选:B.6.解:甲同学在计算时,将分子和分母都乘以(﹣),而﹣是有可能等于0,此时变形后分式没有意义,所以甲同学的解法错误;乙同学的解法正确;故选:B.7.解:∵=3,∴+2=3,∴x=11,y=44,或2+=3,∴x=44,y=11,∴符合题意的正整数对(x,y)的个数是2.故选:B.8.解:若有意义,则,解得3≤x≤5,即x的取值范围是3≤x≤5.∵x是整数,∴x=3或4或5,当x=3时,则=0;当x=4时,则=1;当x=5时,则=0.故选:A.9.解:∵=10,x,y为正整数,∴,化为最简根式应与为同类根式,只能有以下三种情况:+3=+9=4+6=7+3=10.∴,,,共有三组解.故选:C.10.解:∵(x﹣)2=(x+)2﹣4=6﹣4=2,∴x﹣=±.故选C.11.解:若二次根式是最简二次根式,则最小的正整数a为2,故答案为:2.12.解:因为若ab>0,a+b<0,所以a<0,b<0.由于a<0,b<0,与无意义,所以①的变形错误;∵•==1,故②正确;∵÷===|b|,由于b<0,∴原式=﹣b,故③正确;∵•===|a|,由于a<0,∴原式=﹣a,故④计算错误.故答案为②③13.解:∵2205=21,2023<21,∴在,,,……,2023这2023个式子中,与2205可以合并的有20。
2024人教新目标八年级下册英语Unit 2Section B 1a-1e课后练习及答案
Unit 2 I’ll help to clean up the city parks? Section B ( 1a- 1e)课后练习课程基本信息学科英语年级七年级上册课题Unit 2 I’ll help to clean up the city parks? Section B ( 1a- 1e)使用教材人教新目标出版日期2013.05学生信息姓名学校班级学号学习目标1.To learn to talk about offering help2.To learn the new words and expressions: fix up, give away, repair, take after, run out of…课后练习基础过关一、单项选择。
1.His money ________ this morning.A. run out ofB. ran out ofC. run outD. ran out2. . Look! The girl __________.A. take after himB. take him afterC. takes after himD. takes him after3. –My computer is broken.--Why not ask Mr Smith ________ for you?A. to fix up itB. fix up itC. to fix it upD. fix it up4.My idea is similar __________.A. to youB. with youC. to yoursD. with yours5. Mike has to ________ his decision to work hard and never give up.A. makeB. makesC. makingD. made二、单词拼写。
外研版初中英语八下Module 1-3综合测试(包含答案)
外研版初二级英语科模块检测题(一)(内容:Module 1-Module 3 )班级姓名座号评分听力部分(20分)一、听句子:根据句子的内容和所提问题,选择符合题意的图画回答问题。
(5分)( ) 1、Which hobby is Sally interested in the most?A B C ( ) 2、What's David's job?A B C ( ) 3、Where is Sally now?Beijing London Eye ViennaA B C ( ) 4、Which is the right way for you?A B C ( ) 5、What's the girl's favourite job?A B C二、听对话:听下面几段对话,并回答每段对话后面的问题,从题中所给的选项中,选出最佳答案。
(5分)( ) 6、What do you think the woman is?A、A reporter.B、A TV newsreader.C、A presenter.( ) 7、What's the girl's hobby?A、Looking after animals.B、Collecting stamps.C、Learning writing articles.( ) 8、Where does the woman come from?A、China.B、Europe.C、America.( ) 9、How will the weather be like tomorrow?A、It'll be fine.B、It'll be bad.C、I have no idea.( )10、Who is Song Zuying?A、She's a singer.B、She's a actress.C、She's a composer.三、听短文:听下面一段短文,根据录音里的内容,选出最佳答案。
(典型题)初中数学八年级数学下册第五单元《分式与分式方程》检测(答案解析)(1)
一、选择题1.甲乙两地相距60km ,一艘轮船从甲地顺流到乙地,又从乙地立即逆流到甲地,共用8小时,已知水流速度为5km/h ,若设此轮船在静水中的速度为x km/h ,可列方程为( ) A .6060855x x +=+- B .120120855x x +=+- C .6058x+= D .6060855x x +=+- 2.已知112a b -=,则a b ab-的值是( ) A .2 B .2- C .12 D .12- 3.下列各式中,分式有( )个3x ,1n ,15a +,15a b +,2z x y ,()22ab a b + A .4 B .3 C .2 D .14.现在汽车已成为人们出行的交通工具.李刚、王勇元旦那天相约一起到某加油站加油,当天95号汽油的单价为m 元/升,他俩加油的情况如图所示.半个月后的某天,他俩再次相约到同一加油站加油,此时95号汽油的单价下调为n 元/升,他俩加油的情况与上次相同,请运用所学的数学知识计算李刚、王勇两次加油谁的平均单价更低?低多少?下列结论正确的是( )A .李刚比王勇低()22m n mn-元/升B .王勇比李刚低()22mn m n -元/升 C .王勇比李刚低()22m n mn -元/升D .李刚与王勇的平均单价都是2m n +元/升5.定义:若两个分式的和为n (n 为正整数),则称这两个分式互为“n 阶分式”.例如,分式31x +与31x x+互为“3阶分式”.设正数x ,y 互为倒数,则分式22x x y +与22y y x +互为( )A .二阶分式B .三阶分式C .四阶分式D .六阶分式 6.某市铺设一条长660米的管道,为了尽量减少施工对城市交通造成的影响,实际施工时每天铺设的管道长比计划增加10%,结果提前6天完工,求实际每天铺设管道长度及实际施工天数,小明列出方程:660660(110%)x x -+=6,题中x 表示的量为( ) A .实际每天铺设管道长度B .实际施工天数C .计划施工天数D .计划每天铺设管道的长度 7.已知分式34x x -+的值为0,则x 的值是( ) A .3 B .0 C .-3 D .-48.下列变形不正确的是( )A .1122x x x x +-=---B .b a a b c c--+=- C .a b a b m m-+-=- D .22112323x x x x --=--- 9.若a b ,则下列分式化简中,正确的是( )A .22a a b b +=+B .22a a b b -=-C .33a a b b =D .22a a b b= 10.若数a 使关于x 的分式方程2311a x x+=--的解为非负数,且使关于y 的不等式组213202y y y a +⎧->⎪⎪⎨-⎪≤⎪⎩的解集为2y <-,则符合条件的所有整数a 的个数为( ) A .5B .6C .7D .8 11.下列计算正确的是( ) A .22a a a ⋅=B .623a a a ÷=C .2222a b ba a b -=-D .3339()28a a-=- 12.如果分式2121x x -+的值为0,则x 的值是( ) A .1 B .0 C .1- D .±1二、填空题13.已知方程232a a a -+=,且关于x 的不等式组x a x b ≥⎧⎨≤⎩只有3个整数解,那么b 的取值范围是_______.14.已知2a b =,则a b a b +-=_____. 15.若113m n+=,则分式225m n mn m n +---的值为________ . 16.关于x 的分式方程211m x =-+无解,则m 的取值是_______. 17.若x 2-x -1=0,则232x x x --=___. 18.关于x 的方程53244x mx x x ++=--无解,则m =________. 19.若分式方程221422m x x x -=-+-有增根,则m 的值是________. 20.为了创建“最美校园图书屋”,新购买了一批图书,其中科普类图书平均每本书的价格是文学类图书平均每本书价格的1.2倍.已知学校用12000元购买文学类图书的本数比用这些钱购买科普类图书的本数多100本,那么学校购买文学类图书平均每本书的价格是多少元?设学校购买文学类图书平均每本书的价格是x 元,根据题意列方程为____.三、解答题21.先化简,再求值:2221111x x x x x ++⎛⎫-÷ ⎪--⎝⎭,其中 1x =. 22.解方程:(1)81877--=--x x x ; (2)21124x x x -=--. 23.(1)先化简,再求值:2222213214x x x x x x x x -⎛⎫÷-- ⎪+++-⎝⎭,其中12x =. (2)解方程:11322x x x--=--. 24.先化简,再求值:21123369⎛⎫+÷⎪-+-+⎝⎭m m m m m ,其中9m =. 25.(1)化简分式:11222x x x -+---; (2)判断方程112022x x x-+-=--是否有解?_____(填“是”或“否”)26.(1(101320203-⎛⎫--+ ⎪⎝⎭.(2)先化简,再求值:21211x x ++-,其中2021x =.【参考答案】***试卷处理标记,请不要删除一、选择题1.D解析:D【分析】本题关键描述语是:“共用去8小时”.等量关系为:顺流60千米用的时间+逆流60千米用的时间=5,根据等量关系列出方程即可.【详解】 解:由题意,得:6060855x x +=+-, 故选:D .【点睛】本题考查分式方程的应用,分析题意,找到关键描述语,找到合适的等量关系是解决问题的关键.注意顺流速度=静水速度+水流速度;逆流速度=静水速度-水流速度. 2.B解析:B【分析】根据分式的运算法则即可求出答案.【详解】解:∵112a b -=, ∴2b a ab-=, ∴原式=﹣2,故选:B .【点睛】本题考查分式的运算,解题的关键是熟练运用分式的运算法则,本题属于基础题型. 3.A解析:A【分析】分母是整式且整式中含有字母,根据这点判断即可.【详解】∵3x 中的分母是3,不含字母, ∴3x 不是分式; ∵1n 中的分母是n ,是整式,且是字母, ∴1n 是分式; ∵15a +中的分母是a+5,是多项式,含字母a , ∴15a +是分式; ∵15a b +中的分母是15,不含字母, ∴15a b +不是分式; ∵2z x y 中的分母是2x y ,是整式,含字母x ,y , ∴2z x y 是分式; ∵()22ab a b +中的分母是2()a b +,是整式,含字母a ,b , ∴()22ab a b +是分式;共有4个,故选A .【点睛】本题考查了分式的定义,熟练掌握分式构成的两个基本能条件是解题的关键.4.A解析:A【分析】先求解李刚两次加油每次加300元的平均单价为每升:2mn m n +元,再求解王勇每次加油30升的平均单价为每升:2m n +元,再利用作差法比较两个代数式的值,从而可得答案. 【详解】解:李刚两次加油每次加300元,则两次加油的平均单价为每升:()6006002300300300mn m n m n m n mn==+++(元), 王勇每次加油30升,则两次加油的平均单价为每升:3030602m n m n ++=(元), ()()()224222m n m n mn mn m n m n m n ++∴-=-+++ ()()()222222m n m mn n m n m n --+==++ 由题意得:,m n ≠ ()()22m n m n -∴+>0, ∴ 2m n +>2mn m n +. 故A 符合题意,,,B C D 都不符合题意,故选:.A【点睛】本题考查的是列代数式,分式的加减运算,代数式的值的大小比较,掌握以上知识是解题的关键.5.A解析:A【分析】根据题意得出xy =1,可以用1x 表示y ,代入22x x y ++22y y x +,计算结果为2即可. 【详解】由题意得:xy =1,则y =1x , 把 y =1x ,代入22x x y ++22y y x +,得: 原式=221x x x ++221x x x+=3321x x ++321x +=2 ∴22x x y +与22y y x +互为“2阶分式”, 故选A .【点睛】本题是一道新定义型题目,主要考查分式的相关计算,有一定难度,熟练掌握分式的运算法则是解题的关键.6.D解析:D【分析】根据计划所用时间-实际所用时间=6,可知方程中未知数x 所表示的量.【详解】解:设原计划每天铺设管道x 米,则实际每天铺设管道()110%x +, 根据题意,可列方程:6606(110%)660x x -=+, 所以小明所列方程中未知数x 所表示的量是计划每天铺设管道的长度,故选:D .【点睛】本题主要考查由实际问题抽象出分式方程,解题的关键是依据所给方程还原等量关系. 7.A解析:A【分析】根据分式的值为0的条件可以求出x 的值;分式为0时,分子为0分母不为0;【详解】由分式的值为0的条件得x-3=0,x+4≠0,由x-3=0,得x=3,由x+4≠0,得x≠-4,综上,得x=3时,分式34x x -+ 的值为0; 故选:A .【点睛】本题考查了分式的值为0的情况,若分式的值为0,需要同时具备两个条件:(1)分子为0;(2)分母不为0,这两个条件缺一不可. 8.A解析:A【分析】答题首先清楚分式的基本性质,然后对各选项进行判断.【详解】解:A 、1122x x x x +--=---,故A 不正确; B 、b a a b c c--+=-,故B 正确;C 、a b a b m m-+-=-,故C 正确; D 、22112323x x x x--=---,故D 正确. 故答案为:A .【点睛】本题主要考查了分式的基本性质,掌握分式的基本性质是解题的关键.9.C解析:C【分析】根据a b ,可以判断各个选项中的式子是否正确,从而可以解答本题; 【详解】 ∵a b A 、22a a b b +≠+ ,故该选项错误; B 、22a a b b -≠- ,故该选项错误; C 、33a a b b= ,故该选项正确; D 、22a a b b≠ ,故该选项错误; 故选:C .【点睛】本题考查了分式的混合运算,解题时需要熟练掌握分式的性质,分式的分子与分母同乘(或除以)一个不等于0的整式,分式的值不变,熟练掌握分式的基本性质是解题的关键;10.C解析:C【分析】 根据分式方程2311a x x+=--的解为非负数求得a>5,根据不等式组的解集为2y <-,求得2a ≥-,利用分式的分母不等于0得到x ≠1,即可得到a 的取值范围25a -≤≤,且x ≠1,根据整数的意义得到a 的整数值.【详解】 解分式方程2311a x x +=--,得53a x -=, ∵分式方程2311a x x+=--的解为非负数,∴503a -≥, 解得a ≤5, ∵关于y 的不等式组213202y y y a +⎧->⎪⎪⎨-⎪≤⎪⎩,得2y y a <-⎧⎨≤⎩, ∵不等式组的解集为2y <-,∴2a ≥-,∵x-1≠0,∴x ≠1,∴25a -≤≤,且x ≠1,∴整数a 为:-2、-1、0、1、3、4、5,共有7个,故选:C .【点睛】此题考查根据分式方程的解的情况求未知数的取值范围,根据不等式组的解集情况求未知数的取值范围,确定不等式的整数解,正确理解题意并计算是解题的关键.11.C解析:C【分析】A 、B 两项利用同底数幂的乘除法即可求解,C 项利用合并同类项法则计算即可,D 项利用分式的乘方即可得到结果,即可作出判断.【详解】解:A 、原式=a 3,不符合题意;B 、原式=a 4,不符合题意;C 、原式=-a 2b ,符合题意;D 、原式=3278a -,不符合题意, 故选:C .【点睛】此题考查了分式的乘方,合并同类项,以及同底数幂的乘除法,熟练掌握运算法则是解本题的关键. 12.D解析:D【分析】直接利用分式的值为零的条件,即分子为零,分母不为零,进而得出答案.【详解】解:∵分式2121x x -+值为0,∴2x+1≠0,210x -=,解得:x=±1.故选:D .【点睛】此题主要考查了分式的值为零的条件,正确把握分子为零分母不为零是解题关键.二、填空题13.3≤b <4【分析】首先解分式方程求得a 的值然后根据不等式组的解集确定x 的范围再根据只有3个整数解确定b 的范围【详解】解:解方程两边同时乘以a 得:2-a +2a=3解得:a=1∴关于x 的不等式组则解集是解析:3≤b <4【分析】首先解分式方程求得a 的值,然后根据不等式组的解集确定x 的范围,再根据只有3个整数解,确定b 的范围.【详解】 解:解方程232a a a-+=, 两边同时乘以a 得:2-a +2a=3,解得:a=1,∴关于x 的不等式组x a x b ≥⎧⎨≤⎩, 则解集是1≤x≤b ,∵不等式组只有3个整数解,则整数解是1,2,3,∴3≤b <4.故答案是:3≤b <4.【点睛】此题考查的是一元一次不等式组的解法和解分式方程,求不等式组的解集,应遵循以下原则:同大取较大,同小取较小,小大大小中间找,大大小小解不了. 14.3【分析】首先由可设a =2kb =k 然后将其代入即可求得答案【详解】解:∵∴设a =2kb =k ∴==3故答案为:3【点睛】本题考查了分式的化简求值本题的关键是能利用设k 法设出未知数解析:3【分析】 首先由2a b=,可设a =2k ,b =k ,然后将其代入a b a b +-,即可求得答案. 【详解】 解:∵2a b =,∴设a =2k ,b =k , ∴a b a b +-=22k k k k+-=3. 故答案为:3.【点睛】 本题考查了分式的化简求值,本题的关键是能利用设k 法,设出未知数.15.【分析】由可得m+n=3mn 再将原分式变形将分子分母化为含有(m+n )的代数式进而整体代换求出结果即可【详解】解:∵∴即m+n=3mn ∴====故答案为:【点睛】本题考查分式的值理解分式有意义的条件 解析:13- 【分析】 由113m n+=可得m+n=3mn ,再将原分式变形,将分子、分母化为含有(m+n )的代数式,进而整体代换求出结果即可.【详解】 解:∵113m n+=, ∴=3m n mn+,即m+n=3mn , ∴225m n mn m n +--- =()()25+m n mn m n +-- =2353mn mn mn ⋅-- =3mn mn- =13-. 故答案为:13-.【点睛】本题考查分式的值,理解分式有意义的条件,掌握分式值的计算方法是解决问题的关键. 16.【分析】分式方程去分母转化为整式方程由分式方程无解确定出x 的值代入整式方程计算即可求出m 的值【详解】解:去分母得:由分式方程无解得x+1=0即x=-1把x=-1代入得:解得:m=0故答案为:m=0【解析:0m =【分析】分式方程去分母转化为整式方程,由分式方程无解确定出x 的值,代入整式方程计算即可求出m 的值.【详解】解:去分母得:21m x =--,由分式方程无解,得x+1=0,即x=-1,把x=-1代入21m x =--得:2110m =-=,解得:m=0,故答案为:m=0.【点睛】本题主要考查分式方程的解,理解分式方程的增根产生的原因是解题的关键.17.2【分析】把x2-x-1=0变形得x2-1=x 然后对分式进行化简再代入求值【详解】∵x2-x-1=0∴x2-1=x ∵故答案是:2【点睛】本题主要考查分式的化简求值掌握分式的减法运算是解题的关键解析:2【分析】把x 2-x -1=0变形得x 2 -1=x ,然后对分式进行化简,再代入求值.【详解】∵x 2-x -1=0,∴x 2 -1=x , ∵232x x x --=()222221322222x x x x x x x x x----====, 故答案是:2.【点睛】 本题主要考查分式的化简求值,掌握分式的减法运算是解题的关键.18.3或【分析】分式方程无解即化成整式方程时无解或者求得的x 能令最简公分母为0据此进行解答【详解】解:方程两边都乘以(x-4)得整理得:当时即m=3方程无解;当时∵分式方程无解∴x-4=0∴x=4∴解得解析:3或174. 【分析】分式方程无解,即化成整式方程时无解,或者求得的x 能令最简公分母为0,据此进行解答.【详解】解:方程两边都乘以(x-4)得, 5(3)2(4)x mx x -+=-,整理,得:(3)5m x -=-当30m -=时,即m=3,方程无解;当30m -≠时,53x m =-, ∵分式方程无解,∴x-4=0,∴x=4, ∴543m =-, 解得,174m =. 故答案为:3或174. 【点睛】 本题考查了分式方程的解,分式方程无解分两种情况:整式方程本身无解;分式方程产生增根.19.或;【分析】由分式方程有增根得到代入整式方程计算即可求出m 的值;【详解】解:∵去分母得:;∵分式方程有增根∴∴当时则;当时则;故答案为:或;【点睛】此题考查了分式方程的增根增根确定后可按如下步骤进行 解析:4或8-;【分析】由分式方程有增根,得到240x -=,代入整式方程计算即可求出m 的值;【详解】解:∵221422m x x x -=-+-, 去分母得:2(2)2m x x --=+; ∵分式方程221422m x x x -=-+-有增根, ∴240x -=, ∴2x =±,当2x =时,则4m =;当2x =-时,则8m =-;故答案为:4或8-;【点睛】此题考查了分式方程的增根,增根确定后可按如下步骤进行:①化分式方程为整式方程;②把增根代入整式方程即可求得相关字母的值.20.【分析】设文学类图书平均价格为元/本则科普类图书平均价格为元/本根据数量=总价÷单价结合用12000元购买文学类图书的本数比用这些钱购买科普类图书的本数多100本即可得出关于的分式方程【详解】设文学解析:12000120001001.2x x=+ 【分析】设文学类图书平均价格为x 元/本,则科普类图书平均价格为1.2x 元/本,根据数量=总价÷单价结合用12000元购买文学类图书的本数比用这些钱购买科普类图书的本数多100本,即可得出关于x 的分式方程.【详解】设文学类图书平均价格为x 元/本,则科普类图书平均价格为1.2x 元/本, 依题意得:12000120001001.2x x =+. 故答案为:12000120001001.2x x=+. 【点睛】本题考查了分式方程的应用,找准等量关系,正确列出分式方程是解题的关键. 三、解答题21.11x + 【分析】根据分式的运算法则先进行化简,然后代入1x =计算即可.【详解】 原式22121111x x x x x x x -++⎛⎫=-÷ ⎪---⎝⎭, ()()()211111x x x x +-=⨯-+ 11x =+当1x =时,原式2==. 【点睛】本题考查了分式的化简求值,熟练掌握分式的运算法则是解题的关键.22.(1)无解;(2)x =﹣32【分析】(1)分式方程去分母转化为整式方程,求出整式方程的解得到x 的值,经检验即可得到分式方程的解;(2)分式方程去分母转化为整式方程,求出整式方程的解得到x 的值,经检验即可得到分式方程的解.解:(1)去分母得:()8187x x -+=-,整理得:749x =解得:x =7,经检验x =7是原方程的增根,∴原方程无解;(2)去分母得:()2214x x x +-=-, 整理得:23x =-解得:x =32-, 经检验x =﹣32是分式方程的解. 【点睛】 本题考查分式方程的解法,解题的关键是化分式方程为整式方程的方法,同时注意检验方程的根.23.(1)2x x +,15;;(2)3x = 【分析】(1)原式括号中两项通分并利用同分母分式的加法法则计算,同时利用除法法则变形,约分得到最简结果,把12x =代入计算即可求出值; (2)分式方程去分母转化为整式方程,求出整式方程的解得到x 的值,经检验即可得到分式方程的解.【详解】(1)解:原式2222123214x x x x x x x x x +--=÷-+++- ()()()()()22112122x x x x x x x x -+=⋅-++-+ 2222x x x x x x =-=+++ 当12x =原式2x x =+15=; (2)解:去分母得:()1321x x --=-,移项合并得:-2x =-6,解得:3x =,经检验3x =是分式方程的解此题考查了分式的化简求值,熟练掌握运算法则是解本题的关键.24.33-+m m ,12. 【分析】 原式被除数括号中两项通分并利用同分母分式的加法法则计算,除数分母利用完全平方公式分解因式后,再利用除以一个数等于乘以这个数的倒数将除法运算化为乘法运算,约分得到最简结果,将m 的值代入计算即可求出值.【详解】 解:21123369⎛⎫+÷ ⎪-+-+⎝⎭m m m m m =33(3)(3)m m m m ++-+-•2(3)2m m- =33-+m m , 当m =9时,原式=931=932-+. 【点睛】此题考查了分式的化简求值,分式的加减运算关键是通分,通分的关键是找最简公分母;分式的乘除运算关键是约分,约分的关键是找公因式.25.(1)1;(2)否.【分析】(1)原式通分并利用同分母分式的加减法则计算即可求出值;(2)分式方程去分母转化为整式方程,求出整式方程的解得到x 的值,检验即可.【详解】解:(1)11222x x x -+--- =12(2)1222x x x x x --++--- =12412x x x -+-+- =22x x -- =1;(2)去分母得:1-x+2x-4+1=0,解得:x=2,经检验x=2是增根,分式方程无解.故答案为:否.【点睛】此题考查了分式方程的解,以及解分式方程,熟练掌握运算法则是解本题的关键. 26.(1)-1;(2)11x -;12020【分析】(1)根据绝对值化简、负指数幂和零指数幂计算即可;(2)先化简分式,再代入求解即可;【详解】(1)解:原式331=--, 1=-;(2)解:原式221211x x x -=+-- 1(1)(1)x x x +=+- 11x =-, 当2021x =时,原式11202112020==-; 【点睛】本题主要考查了实数的混合运算和分式化简求值,准确计算是解题的关键.。
(常考题)北师大版初中数学八年级数学下册第五单元《分式与分式方程》检测题(答案解析)(1)
一、选择题1.若关于x 的分式方程3111m x x -=--的解是非负数,则m 的取值范围是( ) A .4m ≥-,1m ≠B .4m ≥-且3m ≠-C .2m ≥且3m ≠D .4m >-2.八年级学生去距学校10Km 的春蕾社区参加社会实践活动,一部分学生骑自行车先走,过了20分钟后,其余学生乘汽车出发,结果他们同时到达.已知汽车的速度是骑自行车学生的速度的2倍,求骑自行车学生的速度.若设骑自行车学生的速度为xKm/h ,列方程正确的是( )A .1010302x x -= B .102010602x x += C .1010302x x += D .102010602x x-= 3.已知关于x 的分式方程131k x x =+无解,则k 的值为( ) A .0 B .0或-1 C .-1 D .0或134.某市为有效解决交通拥堵营造路网微循环,决定对一条长1200米的道路进行拓宽改造.为了减轻施工对城市交通造成的影响,实际施工时,每天改造道路的长度比原计划增加20%,结果提前5天完成任务,求实际每天改造道路的长度和实际施工的天数.一位同学列出方程()1200120050120%x x+-=+,则方程中未知数x 所表示的量是( ) A .实际每天改造的道路长度 B .实际施工的天数C .原计划施工的天数D .原计划每天改造的道路长度 5.下列各分式中,最简分式是( )A .6()8()x y x y -+B .22y x x y --C .2222x y x y xy ++D .222()x y x y -+ 6.如图,若x 为正整数,则表示3211327121(1)(1)543x x x x x x x x x--++--÷++++的值的点落在( ).A .段①B .段②C .段③D .段④ 7.下列各式中,正确的是( )A .22a a b b = B .11a a b b +=+ C .2233a b a ab b = D .232131a a b b ++=-- 8.已知2,1x y xy +==,则y x x y +的值是( ) A .0 B .1 C .-1 D .29.若x 2y 5=,则x y y+的值为( ) A .25 B .72 C .57 D .7510.已知:x 是整数,12,21x x M N x +==+.设2y N M =+.则符合要求的y 的正整数值共有( )A .1个B .2个C .3个D .4个 11.若关于x 的分式方程222x m x x =---的解为正数,则满足条件的正整数m 的值为( )A .1,2,3B .1,2C .2,3D .1,312.下列计算正确的是( )A .22a a a ⋅=B .623a a a ÷=C .2222a b ba a b -=-D .3339()28a a-=- 二、填空题13.设m ,n 是实数,定义关于@的一种运算如下:22@()()m n m n m n =+--,则下列结论:①若0mn ≠,m@8n =,则223944163m m n n ÷=; ②@()@@m n k m n m k -=-;③不存在非零实数m ,n ,满足22@5m n m n =+;④若设2m ,n 是长方形的长和宽,若该长方形的周长固定,则当m n =时,@m n 的值最大.其中正确的是_____________.14.若113m n+=,则分式225m n mn m n +---的值为________ . 15.已知5,3a b ab -==,则b a a b+的值是__________.16.化简分式:2121211a a a a +⎛⎫÷+= ⎪-+-⎝⎭_________. 17.H 7N 9病毒直径为30纳米(1纳米=10-9米),用科学记数法表示这个病毒直径的大小为________米.18.已知215a a+=,那么2421a a a =++________. 19.对于每个非零自然数n ,x 轴上有(,0)n A x ,(,0)n B y 两点,以n n A B 表示这两点间的距离,其中n A ,n B 的横坐标分别是方程组1121111n x y x y⎧+=+⎪⎪⎨⎪-=-⎪⎩的解,则112220202020A B A B A B +⋅⋅⋅++的值等于_______.20.若()()023248x x ----有意义,则x 的取值范围是______. 三、解答题21.解方程:32122x x x =--- 22.计算题:(1)- (2)(2a )3·b 4÷8a 3b 2 (3)(-a b )2·(-22b a)3÷(-ab 4) (4)()(5)1-2222244a b a b a b a ab b--÷+++ (6)(x -y +4xy x y -)(x +y -4xy x y+) 23.根据已知条件,求下列各式的值:()1已知3,2m n x x ==,求32m n x +的值;()2先化简:2211121x x x x x x ⎛⎫ ⎪+++÷--⎝+⎭,然后从22x -≤≤中选取一个合适的整数作为x 的值代入求值.24.为预防新冠疫情的反弹,康源药店派采购员到厂家去购买了一批A 、B 两种品牌的医用外科口罩.已知每个B 品牌口罩的进价比A 品牌口罩的进价多0.7元,采购员用7200元购进A 品牌口罩的数量为用5000元购进B 品牌数量的2倍.(1)求A 、B 两种品牌每个口罩的进价分别为多少元?(2)若B 品牌口罩的售价是A 品牌口罩的售价的1.5倍,要使康源药店销售这批A 、B 两种品牌口單的利润为8800元,则它们的售价分别定为多少元?25.(1)计算:()24342a b ab ÷-(2)解方程:1233x x x-=-- 26.为支援贫困山区,某学校爱心活动小组准备用筹集的资金购买A 、B 两种型号的学习用品.已知B 型学习用品的单价比A 型学习用品的单价多10元,用180元购买B 型学习用品与用120元购买A 型学习用品的件数相同.(1)求A 、B 两种学习用品的单价各是多少元;(2)若购买A 、B 两种学习用品共1000件,且总费用不超过28000元,则最多购买B 型学习用品多少件?【参考答案】***试卷处理标记,请不要删除一、选择题1.B解析:B【分析】先去分母得到整式方程m +3=x ﹣1,再由整式方程的解为非负数得到m +4≥0,由整式方程的解不能使分式方程的分母为0得到m +4≠1,然后求出不等式的公共部分得到m 的取值范围.【详解】解:去分母得m +3=x ﹣1,整理得x =m +4,因为关于x 的分式方程311m x x-=--1的解是非负数, 所以m +4≥0且m +4≠1,解得m ≥﹣4且m ≠﹣3,故选:B .【点睛】 本题考查了分式方程的解:求出使分式方程中令等号左右两边相等且分母不等于0的未知数的值,这个值叫方程的解.在解方程的过程中因为在把分式方程化为整式方程的过程中,可能产生增根,增根是令分母等于0的值,不是原分式方程的解.2.D解析:D【分析】设骑车学生每小时走x 千米,则设乘车学生每小时走2x 千米,根据题意可得等量关系:骑车学生所用时间-乘车学生所用时间=20分钟,根据等量关系列出方程即可.【详解】解:设骑车学生每小时走x 千米,则设乘车学生每小时走2x 千米,由题意得: 102010602x x-=, 故选:D .【点睛】此题主要考查了由实际问题抽象出分式方程,关键是正确理解题意,找出题目中的等量关系,列出方程.3.D解析:D【分析】此题考查了分式方程的解,始终注意分母不为0这个条件,分式方程去分母转化为整式方程,由分式方程无解确定出k 的值即可.【详解】解:分式方程去分母得:33x kx k =+ ,即 ()313k x k -=- ,当310k -=,即 13k =时,方程无解; 当x=-1时,-3k+1=-3k ,此时k 无解;当x=0时,0=-3k ,k=0,方程无解; 综上,k 的值为0或13 . 故答案为:D .【点睛】本题考查了根据分式方程的无解求参数的值,是需要识记的内容.分式方程无解的条件是:去分母后所得整式方程无解,或解这个整式方程得到的解使原方程的分母等于0. 4.D解析:D【分析】根据提前天数+实际工作用天数-原计划天数=0,可以判断方程中未知数x 表示的量.【详解】设原计划每天铺设管道x 米,则实际每天改造管道(1+20%)x ,根据题意,可列方程: ()1200120050120%x x+-=+, 所以所列方程中未知数x 所表示的量是原计划每天改造管道的长度,故选:D .【点睛】本题考查了由实际问题布列分式方程,解题的关键是依据所给方程等量关系.5.C解析:C【分析】分式的分子和分母没有公因式的分式即为最简分式,根据定义解答.【详解】A 、6()8()x y x y -+=3()4()x y x y -+,故该项不是最简分式; B 、22y x x y--=-x-y ,故该项不是最简分式; C 、2222x y x y xy ++分子分母没有公因式,故该项是最简分式; D 、222()x y x y -+=x y x y -+,故该项不是最简分式; 故选:C .【点睛】此题考查最简分式定义,化简分式,掌握方法将分式的化简是解题的关键.6.B解析:B【分析】将原式分子分母因式分解,再利用分式的混合运算法则化简,最后根据题意求出化简后分式的取值范围,即可选择.【详解】 原式221(1)71211543(1)x x x x x x x -++=-++++ 1(3)(4)11(1)(4)3xx x x xx x x x-++=-++++ 1111x x x -=-++ 1x x =+ 又因为x 为正整数,所以11 21xx≤<+,故选B.【点睛】本题考查分式的化简及分式的混合运算,最后求出化简后的分式的取值范围是解答本题关键.7.C解析:C【分析】利用分式的基本性质变形化简得出答案.【详解】A.22a ab b=,从左边到右边是分子和分母同时平方,不一定相等,故错误;B.11a ab b+=+,从左边到右边分子和分母同时减1,不一定相等,故错误;C.2233a b aab b=,从左边到右边分子和分母同时除以ab,分式的值不变,故正确;D.232131a ab b++=--,从左边到右边分子和分母的部分同时乘以3,不一定相等,故错误.故选:C.【点睛】本题考查分式的性质.熟记分式的性质是解题关键,分式的分子与分母同乘(或除以)一个不等于0的整式,分式的值不变.8.D解析:D【分析】将y xx y+进行通分化简,整理出含已知条件形式的分式,即可得出答案.【详解】解:2222()2221 =21y x y x x y xyx y xy xy++--⨯+===故选D.【点睛】本题考查了分式的混合运算,熟练运用完全平方公式是解题的关键.9.D解析:D【分析】根据同分母分式的加法逆运算得到x y x y y y y +=+,将x 2y 5=代入计算即可. 【详解】 解:∵x 2y 5=, ∴x y x y 2y y y 5+=+=+175=, 故选:D .【点睛】此题考查同分母分式的加减法,已知式子的值求分式的值.10.C解析:C【分析】先求出y 的值,再根据x ,y 是整数,得出x +1的取值,然后进行讨论,即可得出y 的正整数值.【详解】解:∵12,21x x M N x +==+ ∴42222221111x x y x x x x ++=+==+++++. ∵x ,y 是整数, ∴21x +是整数, ∴x +1可以取±1,±2.当x +1=1,即x =0时2241y =+=>0; 当x +1=−1时,即x =−2时,2201y =+=-(舍去); 当x +1=2时,即x =1时,2232y =+=>0; 当x +1=−2时,即x =−3时,2212y =+=->0; 综上所述,当x 为整数时,y 的正整数值是4或3或1.故选:C .【点睛】 此题考查了分式的加减法,熟练掌握分式的加减运算法则,求出y 的值是解题的关键. 11.D解析:D【分析】根据等式的性质,可得整式方程,根据解整式方程,可得答案.【详解】等式的两边都乘以(x - 2),得x = 2(x-2)+ m ,解得x=4-m ,且x≠2,由关于x 的分式方程的解为正数,∴4-m >0,4-m≠2∴m<4且m≠2则满足条件的正整数 m 的值为m=1,m=3,故选: D.【点睛】本题考查了分式方程的解,利用等式的性质得出整式方程是解题关键,注意要检验分式方程的根.12.C解析:C【分析】A 、B 两项利用同底数幂的乘除法即可求解,C 项利用合并同类项法则计算即可,D 项利用分式的乘方即可得到结果,即可作出判断.【详解】解:A 、原式=a 3,不符合题意;B 、原式=a 4,不符合题意;C 、原式=-a 2b ,符合题意;D 、原式=3278a -,不符合题意, 故选:C .【点睛】此题考查了分式的乘方,合并同类项,以及同底数幂的乘除法,熟练掌握运算法则是解本题的关键. 二、填空题13.②③④【分析】根据所给新定义可得再分别判断【详解】解:∵①∴==8∴mn=2∴故错误;②=∴故正确;③∴∴当m-2n=0n=0∴m=0∴不存在非零实数mn 满足故正确;④∵m@n=(m+n )2-(m-解析:②③④【分析】根据所给新定义,可得22@()()4m n n m n m m n =-=+-,再分别判断.【详解】解:∵22@()()4m n n m n m m n =-=+-,①22m@()()8n m n m n =+--=,∴22()()m n m n +--=4mn =8,∴mn=2, ∴222239316241649334m m m n n n n m mn ÷=⨯==,故错误; ②()()22@()m n k m n k m n k -=+---+=4()m n k -, ()@@444m n m k mn mk m n k -=-=-,∴@()@@m n k m n m k -=-,故正确;③22@45m n mn m n ==+,∴22540m n mn +=-,∴()2220m n n -+=, 当m-2n=0,n=0,∴m=0,∴不存在非零实数m ,n ,满足22@5m n m n =+,故正确;④∵m@n=(m+n )2-(m-n )2=4mn ,(m-n )2≥0,则m 2-2mn+n 2≥0,即m 2+n 2≥2mn ,∴m 2+n 2+2mn≥4mn ,∴4mn 的最大值是m 2+n 2+2mn ,此时m 2+n 2+2mn=4mn ,解得m=n ,∴m@n 最大时,m=n ,故正确,故答案为:②③④.【点睛】本题考查因式分解的应用、整式的混合运算,分式的乘除,解题的关键是明确题意,找出所求问题需要的条件.14.【分析】由可得m+n=3mn 再将原分式变形将分子分母化为含有(m+n )的代数式进而整体代换求出结果即可【详解】解:∵∴即m+n=3mn ∴====故答案为:【点睛】本题考查分式的值理解分式有意义的条件 解析:13- 【分析】 由113m n+=可得m+n=3mn ,再将原分式变形,将分子、分母化为含有(m+n )的代数式,进而整体代换求出结果即可.【详解】 解:∵113m n +=,∴=3m n mn +,即m+n=3mn , ∴225m n mn m n+--- =()()25+m n mn m n +-- =2353mn mn mn⋅-- =3mn mn- =13-. 故答案为:13-.【点睛】本题考查分式的值,理解分式有意义的条件,掌握分式值的计算方法是解决问题的关键. 15.【分析】先利用乘法公式算出的值再根据分式的加法运算算出结果【详解】解:∵∴∴故答案为:【点睛】本题考查分式的求值解题的关键是掌握分式的加法运算法则 解析:313【分析】先利用乘法公式算出22a b +的值,再根据分式的加法运算算出结果.【详解】解:∵5a b -=,3ab =,∴()222225631a b a b ab +=-+=+=, ∴22313b a b a a b ab ++==. 故答案为:313. 【点睛】本题考查分式的求值,解题的关键是掌握分式的加法运算法则. 16.【分析】先计算括号内的加法再将除法化为乘法再计算乘法即可【详解】解:===故答案为:【点睛】本题考查分式的混合运算掌握运算顺序和每一步的运算法则是解题关键 解析:11a -【分析】先计算括号内的加法,再将除法化为乘法,再计算乘法即可.【详解】 解:2121211a a a a +⎛⎫÷+ ⎪-+-⎝⎭ =2112211a a a a a +-+÷-+- =211(1)1a a a a +-⋅-+ =11a -, 故答案为:11a -. 【点睛】本题考查分式的混合运算.掌握运算顺序和每一步的运算法则是解题关键.17.【分析】根据题意列得这个病毒直径为计算并用科学记数法表示即可【详解】故答案为:【点睛】此题考查实数的乘法计算科学记数法正确理解题意列式并会用科学记数法表示结果是解题的关键解析:8310-⨯【分析】根据题意列得这个病毒直径为93010-⨯,计算并用科学记数法表示即可.【详解】983010310--⨯=⨯,故答案为:8310-⨯ .【点睛】此题考查实数的乘法计算,科学记数法,正确理解题意列式并会用科学记数法表示结果是解题的关键.18.【分析】将变形为=5a 根据完全平方公式将原式的分母变形后代入=5a 即可得到答案【详解】∵∴=5a ∴故答案为:【点睛】此题考查分式的化简求值完全平方公式根据已知等式变形为=5a 将所求代数式的分母变形为 解析:124【分析】 将215a a+=变形为21a +=5a ,根据完全平方公式将原式的分母变形后代入21a +=5a ,即可得到答案.【详解】∵215a a+=, ∴21a +=5a , ∴2421a a a =++()()2222222221242451a a a a a a a a ===-+- 故答案为:124. 【点睛】此题考查分式的化简求值,完全平方公式,根据已知等式变形为21a +=5a ,将所求代数式的分母变形为22(1)a a +-形式,再代入计算是解题的关键. 19.【分析】将n 看做已知数求出方程组的解表示出x 与y 列举出所求式子各项拆项后抵消即可得到结果【详解】解:方程组①+②得即将代入①得:∴∵n >0∴是该方程组的根∴则原代数式故答案为:【点睛】此题考查了分式 解析:20202021【分析】将n 看做已知数求出方程组的解表示出x 与y ,列举出所求式子各项,拆项后抵消即可得到结果.【详解】 解:方程组1121111n x y x y⎧+=+⎪⎪⎨⎪-=-⎪⎩①②, ①+②得22n x =,即1x n =, 将1x n =代入①得:11y n =+, ∴111x n y n ⎧=⎪⎪⎨⎪=⎪+⎩, ∵n >0, ∴111x n y n ⎧=⎪⎪⎨⎪=⎪+⎩是该方程组的根, ∴111n n A B n n =-+,则原代数式1111112020112232020202120212021=-+-+⋯+-=-=. 故答案为:20202021. 【点睛】 此题考查了分式的加减法,解二元一次方程组,以及坐标与图形性质,熟练掌握运算法则是解本题的关键.20.且【分析】根据0指数幂及负整数指数幂有意义的条件列出关于x 的不等式组求出x 的取值范围即可【详解】解:∵(x-3)0-(4x-8)-2有意义∴解得x≠3且x≠2故答案为:x≠3且x≠2【点睛】本题考查解析:2x ≠,且3x ≠【分析】根据0指数幂及负整数指数幂有意义的条件列出关于x 的不等式组,求出x 的取值范围即可.【详解】解:∵(x-3)0-(4x-8)-2有意义,∴30480x x -≠⎧⎨-≠⎩, 解得x≠3且x≠2.故答案为:x≠3且x≠2.【点睛】本题考查的是负整数指数幂,熟知非0数的负整数指数幂等于该数正整数指数幂的倒数是解答此题的关键.三、解答题21.76x =. 【分析】 方程两边同时乘以2(x-1),把分式方程转化为整式方程求解即可.【详解】解:方程两边同时乘以2(x-1),得234(1)x x =--,去括号,得2344x x =-+,移项,合并同类项,得67x =,系数化为1,得6经检验,76x =是原方程的根, 所以原方程的解为76x =. 【点睛】本题考查了分式方程的解法,熟练确定最简公分母是解题的关键,解后要验根是注意事项,不能漏落.22.(1;(2)2b ;(3)218a ;(4)2+5)b a b -+(6)22x y -【分析】(1)先化为最间二次根式,再合并同类二次根式即可;(2)先算积的乘方再算同底数幂乘除法即可;(3)先算分式的乘方,再约分,最后计算分式除法;(4)先计算二次根式的除法,转化为二次根式除以二次根式即可;(5)先进行分子分母因式分解,同时把除法转化为乘法,约分,再通分,合并即可; (6)先将括号内通分,利用公式变形,再约分,最后利用平分差公式展开即可.【详解】解:(1)- ,=-,== (2)(2a )3·b 4÷8a 3b 2 =8 a 3·b 4÷8a 3b 2,=b 2;(3)(-a b )2·(-22b a)3÷(-ab 4), =()264238a b ab b a ⎛⎫⋅-÷- ⎪⎝⎭, =()448b ab a -÷-,28a(4)(),==(5)1-2222244a b a b a b a ab b--÷+++, =()()()2212a b a b a b a b a b +--⋅++-, =()()2a b a b a b a b ++-++, =b a b -+; (6)(x -y +4xy x y -)(x +y -4xy x y+), =()()22x-y +4x+y 4x+y xyxy x y-⋅-, =()()22x+y x-y x+y x y ⋅-,=()()x+y x y -,=22x y -.【点睛】本题考查二次根式加减乘除混合运算,幂指数乘除混合运算,分式的乘法乘除混合运算,分式加减乘除混合运算,掌握二次根式加减乘除混合运算,幂指数乘除混合运算,分式的乘法乘除混合运算,分式加减乘除混合运算是解题关键.23.()1108;()2221x x -+;x=-2时,6或x=2时,23 【分析】(1)利用幂指数运算的逆运算原式()()32mn x x =⋅,当3,2m n x x ==时,整体代入求值即可;(2)先化简分式,从不等式中可选取-2或2,可任选一个代入求值即可.【详解】解: ()1原式=32m n x x ⋅()()32mn x x =⋅, 当3,2m n x x ==时,原式108=;()2原式=22112111x x x x x x x x ⎛⎫ +--+⎝⨯-⎭+-+⎪, =()()21211x x x x x -⨯-+, 221x x -=+, 在22x -≤≤范围内有整数x=-2,-1,0,1,2,使分式有意义的x 的值:x=-2,2,当2x =-时,原式6=;当2x =时,原式23=. 【点睛】本题考查幂指数运算求值,和分式化简求值,掌握幂指数运算求值的方法,和分式化简求值方法是解题关键.24.(1)A 、B 两种品牌每个口罩的进价分别为每个1.8元,2.5元;(2)A 、B 两种品牌每个口罩的售价分别定为每个3元,4.5元.【分析】(1)设A 种品牌每个口罩的进价为每个x 元,则B 种品牌每个口罩的进价为每个()0.7x +元,则可列方程7200500020.7x x =⨯+,解方程并检验即可得到答案; (2)设A 品牌口罩的售价为每个y 元,则B 品牌口罩的售价为每个1.5y 元, 由(1)得:A 品牌口罩的数量为7200=40001.8个,B 品牌口罩的数量为2000个,再列方程()()4000 1.820001.5 2.58800,y y -+-= 解方程可得答案.【详解】解:(1)设A 种品牌每个口罩的进价为每个x 元,则B 种品牌每个口罩的进价为每个()0.7x +元,则7200500020.7x x =⨯+ 1825,0.7x x ∴=+ 251812.6x x ∴=+712.6,x ∴=1.8,x ∴=经检验: 1.8x =是原方程的根,且符合题意,1.82.5x ∴+=即A 、B 两种品牌每个口罩的进价分别为每个1.8元,2.5元.(2)设A 品牌口罩的售价为每个y 元,则B 品牌口罩的售价为每个1.5y 元, 由(1)得:A 品牌口罩的数量为7200=40001.8个,B 品牌口罩的数量为2000个, 则()()4000 1.820001.5 2.58800,y y -+-=17.552.5,y ∴=3y ∴=1.5 4.5,y ∴=答:A 、B 两种品牌每个口罩的售价分别定为每个3元,4.5元.【点睛】本题考查的是一元一次方程的应用,分式方程的应用,掌握利用相等关系列方程解决实际问题是解题的关键.25.(1)2a b ;(2)7x =是原方程的解.【分析】(1)单项式与单项式相除,系数与系数相除作为商的系数,相同字母分别相除,底数不变,指数相减计算即可;(2)等式两边同时乘以x-3化为整式方程,从而求出x 的值,再检验即可;【详解】(1)原式()432244a b a b =÷2a b =(2)解:方程左右两边乘()3x -得()123x x +=-126x x +=-7x =检验7x =时,30x -≠,∴7x =是原方程的解;【点睛】本题考查了单项式与单项式相除和解分式方程,掌握计算方法是解题的关键; 26.(1)A 型学习用品的单价为20元,B 型学习用品的单价为30元;(2)最多购买B 型学习用品800件.【分析】(1)设A 型学习用品单价x 元,利用“用180元购买B 型学习用品的件数与用120元购买A 型学习用品的件数相同”列分式方程求解即可;(2)设可以购买B 型学习用品y 件,则A 型学习用品(1000−y )件,根据这批学习用品的钱不超过28000元建立不等式求出其解即可.【详解】解:(1)设A 型学习用品的单价为x 元,则B 型学习用品的单价为(x +10)元,由题意得:18012010x x=+, 解得:x =20,经检验x =20是原分式方程的根,且符合实际,则x +10=30.答:A 型学习用品的单价为20元,B 型学习用品的单价为30元;(2)设购买B 型学习用品y 件,则购买A 型学习用品(1000−y )件,由题意得:20(1000−y )+30y≤28000,解得:y≤800.答:最多购买B 型学习用品800件.【点睛】本题考查了列分式方程解应用题和一元一次不等式解实际问题的运用,找到数量关系,列出分式方程和一元一次不等式,是解题的关键.。
牛津译林版8A Unit1 Friends单元练习(含答案与解析)
8A Unit1 单元检测满分:100 时间:60分钟I. 单项选择(每小题1分, 共15分)1. -Andy is really __________ honest boy.-Yes. That's why he is _________ most popular student in his class.A. an; anB. an; theC. a; theD. the; /2. Dad doesn't always come to you. You have to fight and save _____________!A. yourselfB. himselfC. myselfD. herself3. Susan never gets unhappy when she has to wait in line. She is very ___________.A. shyB. honestC. funnyD. patient4. Tony is an honest boy and he never tells a lie. We all ___________him.A. seeB. missC. hateD. trust5. As a teacher, I really feel worried to see so many students __________ glasses.A. wearingB. dressingC. putting onD. being in6. -When is the __________ time to visit Brazil?-In August and September, I think. Not too cold, and not too hot.A. hottestB. hotterC. bestD. better7. -When can I come if I meet with problems?-___________________. I'm always in.A. AnytimeB. You need to call firstC. You'd better notD. I'm afraid not8. My cousin likes ___________ jokes and he never _________ bad words about others.A. saying; tellsB. to tell; sayC. telling; saysD. to say; tells9. Everyone knows that China is getting __________________.A. strong and strongB. strongest and strongestC. stronger and strongerD. more and more strong10. -There is ________________ in Tina's WeChat shop.-So that's why I decide to buy the present in _____________ shop.A. something special; otherB. special something; the otherC. nothing special; anotherD. special nothing; others11. Mount Lao is one of _________mountains in Qingdao. Many tourists like climbing it everyyear.A. famousB. the more famousC. most famousD. the most famous12. -I don't have enough money to buy the white dress.-What about the orange one? The price is a little ________________.A. cheaperB. higherC. lowerD. more expensive13. Miho is ___________student because she was born later than anyone else in her class.A. youngB. youngerC. the youngerD. the youngest14. -What does your brother look like?-__________________________.A. He is outgoingB. He is really tall and thinC. He is a studentD. He is in hospital15. -Is Tina _____________ than Tara?-Yes, but Tara is _____________ in her class.A. taller; the heaviestB. tall; heavyC. taller; heavierD. the tallest; the heaviestII. 完形填空(每小题1分, 共10分)Hi, I am Millie. This is Nancy. She is one of my best friends in China. She is my true friend. She never 16 others my secrets. She is a good girl 17 she has poor eyesight. She likes watching TV and reading books 18 bed. She always 19 a pair of round glasses. She likes singing and she is a fan of Liu Ruoying.Nancy's hair is 20 . At weekends, she likes going 21 in the supermarket. Sometimes she doesn't buy 22 .But she says, "It is very important for all of you to be in a good mood (心情) and relax (放松) 23 . "We must have some good friends. When you need help, you can 24 your best friend. Do you agree 25 me?16. A. says B. talks C. speaks D. tells17. A. or B. and C. if D. so18. A. at B. in C. out D. with19. A. puts B. wears C. dresses D. puts on20. A. as long as me B. so long as meC. as long as mineD. so long as mine21. A. swimming B. boating C. skating D. shopping22. A. nothing B. something C. anything D. none23. A. you B. yours C. yourself D. yourselves24. A. think of B. think over C. think about D. think through25. A. at B. with C. on D. inIII. 阅读理解(每小题2分, 共20分)AJack is 17 years old. He has many friends. They look different and they have differentA. JackB. AnnC. JimD. Lily27. What does Ann like doing?A. Playing basketball.B. Reading.C. Playing computer games.D. Listening to pop songs.28. Why do people say Jim is a "sunshine boy"?A. Because he likes reading.B. Because he likes playing computer games.C. Because he is always smiling.D. Because he is a skier.29. Which of the following is NOT TRUE about Lily?A. She likes wearing a dress.B. She wears black glasses.C. She plays basketball well.D. She has short hair.30. Which of the following is NOT true according to the passage?A. "Angel" does well in playing basketball.B. Lily is the youngest of the three.C. Ann has a baby face.D. Jim likes black horses.BVanilla is my best friend. She is a lovely girl with two big, beautiful eyes. But she always hides them behind a pair of black glasses.One day, though, I nearly ended our friendship. I remember that day clearly. We were sitting in the classroom.The teacher was giving us our results of a Chinese test. I had done badly. I felt so sad that I wouldn't talk to anyone. At lunchtime, I even stayed in the classroom alone. Suddenly, I heard a voice. It was Vanilla. "You look very unhappy," she said. " What's wrong?" I looked up at her, but said nothing. I knew Vanilla had got a good mark in the test. I thought she was making fun of me. I stayed silent, but Vanilla didn't go away. She kept asking me questions:“Is it because of the exam? Do you want me to show you the right answers?" I looked away from her. When I looked up again, Vanilla had gone. And so had my exam paper! I didn't know what to do. I looked everywhere for my paper, but I couldn't find it.In the afternoon, Vanilla came up to my desk and gave me my exam paper back. I looked at it and got a big surprise. Vanilla had written the right answer next to every one of my mistakes. My face went red. Vanilla had been trying to help me all along. How mean I had been to her when she was being so nice. I wanted to hug her, but all I did was to hold her hands and say, "Thank you. " That afternoon, Vanilla and I walked home together. I felt so happy that I had to thank her again. We were still best friends.31. What class was the writer having that day?A. A maths class.B. An English class.C. A Chinese class.D. A history class.32. The writer felt sad because ____________ in the Chinese test.A. she got a good markB. Vanilla had done better than herC. she didn't have a good markD. the teacher was angry with her33. Vanilla came to the writer to ____________________.A. make fun of herB. find out what had happened to herC. borrow something from herD. show her the right answers34. Vanilla left the writer because she _________________________.A. wanted to write the right answers for the writerB. didn't know what to do to help her friendC. was angry with the writerD. wanted to go home for lunch35. Which of the following has the same meaning as "making fun of"?A. Saying "hello" to.B. Seeing me off.C. Laughing at.D. Looking after.IV. 词汇(每小题1分, 共10分)A.根据句意及提示完成单词。
8A_unit1-3单元测试英语试卷_内附答案
8A unit1-3单元测试英语试卷(考试时间:100分钟,总分:100分)一听力I、根据所听内容,将下列图片排序。
A BC D1.________2. ___________3._________4. ___________II、听录音选择合适的应答句。
1 A Thank you . B No, it‟s not good. C You‟re welcome.2 A In a week. B Two months. C Twice a month.3 A He is tall. B He is Sam. C It‟s Sam‟s.4 A Thirty dollars. B It‟s seven o‟clock. C Three years ago.5 A Yes, I can. B No, I don‟t. C No, he, can‟t.6 A Fine. B December 25th C Wednesday D 30th of FebruaryIII、听一段对话回答11---12小题11What are they talking about?A A photo.B A newspaper.C A magazine.12 what do you know about Tom?A He is shorter than Maria.B he is younger than Maria.C He is thinner than Maria.听一段对话回答13—15小题。
13What‟s the date today?A March 5thB March 15thC March 25th14What‟s wrong with Wu Dong?A He has got a bad cold.B He was badly hurt.C He has broken his leg.15What are they going to do after school?A Play basketball.B Go to see Wu Dong.C Go to the cinema. IV、听短文选择正确答案。
人教版八年级英语上第一单元8a unit1
最新人教版八年级英语上第一单元8A U n i t1-CAL-FENGHAI.-(YICAI)-Company One18A Unit 1Where did you go on vacation?第1课时Section A 1a — 1c (P1)【学习目标】【学习重点】:一般过去时的where问句及答语。
1.A 1)三天前 _______________ 2)昨天晚上 ____________________________3)今天早上 __________________ 4)昨天__________________________________5)前天 ______________________ 6)上周______________________________________ 7)去年 ___________________________8)上周六________________________________ B写出下列动词的过去式或原形stay__________________ visited ____________ swim ________study _______________ was _____________ were _____________C 1).呆在家_________________ 2).去爬山____________________3)去纽约市_____________________ 4). 去海滩 ______________________5). 看望我的叔叔___________________ 6). 参观博物馆___________________7). 去参加夏令营_______________ 8)go 的过去式_____________2.掌握主要句式。
①―Where did you go on vacation―I went to summer camp …3、认真观察1a的图画,将词语与图片搭配,并核对答案。
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2008学年第二学期学生纸笔测验评价培训资料八年级英语单元练习答案(Unit 5)二、语言知识与运用(20%)第一节:单项选择1-5 ABCDB 6-10 CCABC第二节:语法填空11-15 DDBAA 16-20 BDBAD三、完型填空(10%)21-25 ACDAA 26-30 DBBAB四、阅读理解(20%)31-35 CDDCB五、写作(25%)第一节:根据首字母的提示完成句子。
(5%)36. professor 37.unhappy 38. argument 39.budget 40. suggestion第二节:改写句子,每格0.5分。
(10%)41. told not to be the next day 42. asked to tell him(her) his 43. she would go her that 44. which she liked第三节:根据所给中文完成句子。
(10%)45. sometimes get angry with 46. pays for 47. was doing washing called 48. for nothing 49. looking forward to meeting第三节:书面表达(10%)Possible versionI am the only child in my family. I study at No. 3 Middle School. I like collecting stamps and pop music. I tidy my bedroom once a week; I wash clothes and often help my mother do the housework. I also learn to cook meals. Though the food doesn’t taste good, my parents like it. On weekdays, I am not allowed to play the computer, but I can watch the news everyday. They ask me not to waste pocket money. I can use the money to buy some useful books. If I want to go out at night, I must ask my parents first. I must come back home before 9 o’clock. My parents are strict with me, but I love them very much.2008学年第二学期学生纸笔测验评价培训资料八年级英语单元练习答案(Unit 6)二、语言知识与运用(20%)第一节:单项选择1-5 CCDDA 6-10 BDBCA第二节:语法填空11-15 B D C B C 16-20 D A C C D三、完形填空(10%)21-25 DBACA 26-30 BCDBD四、阅读理解(20%)31-35DDACD五、写作(25%)第一节:用所给单词的适当形式填空(5%)36. kite 37. sort 38. escaped 39. considered 40. persuaded第二节:按要求改写句子。
(10%)41. seen here and there 42. called out 43. argued with 44. What they were looking 45. was painted well by第三节:根据所给中文完成句子。
(10%)46. reached(arrived), had a rest 47. called out there 48. has her own way 49. dug up 50. will be set free第四节:书面表达(10%)Tom Sawyer was born in Mississippi. He lived with his Aunt Polly. He was lively, naughty, smart and brave. Huckleberry Finn was his best friend. Tom Sawyer and his best friend often told stories and went fishing by the Mississippi River. Tom liked exploration with his friends. He could find many interesting things in the adventures. Once, he was the eyewitness of a murder. He told the judge the truth and saved Muff.2008学年第二学期学生纸笔测验评价培训资料八年级英语单元练习答案(Unit 7)二、语言知识与运用(20%)第一节:单项选择1-5 BDCCA 6-10 ACABD第二节:语法填空11-15CBDAD16-20CDBBA三、完形填空(10%)21-25CABAC 26-30 DBDBA四、阅读理解(20%)31-35ABDCD 36-40 CADBC五、写作(25%)第一节:根据首字母的提示完成句子。
(5%)41.weak 42. order 43. store 44. weigh 45.pity第二节:根据所给中文完成句子。
(10%)46. not to make, noise 47. succeeded in losting weight 48. keeps trouble for herself 49. A long time ago 50. in need, for free(for nothing)第三节:书面表达(10%)As we know, learning English well is not an easy job. First, we should listen carefully in class, and write down the notes. Second, we should remember the words and phrases by heart every day. It’s easy for us to forget the words if we don’t use it often. So we should try to use the words, especially the new ones. Third, we should read the texts loudly, or read after the tapes. Finally, we should insist on doing some reading and some English exercises every day. If we can do above, we’re sure that we can learn English well.2008学年第二学期学生纸笔测验评价培训资料八年级英语单元练习答案(期末测试卷)二、语言知识与运用(20%)第一节:单项选择1-5CBCD 6-10 BCDAC第二节:语法填空11-15 A BCAA 16-20 A DCBC三、完形填空(10%)21-25 CDBAC 26-30 ACABC四、阅读理解(20%)31-35 DDDCB 36-40 BCDAD 41-45 AABDB五、写作(25%)第一节:根据首字母的提示完成句子。
(5%)46. exchange 47. including 48. stranger 49. scholarship 50. pavement第二节:根据句子意思,改写句子(10%)51. at the age of 52. asked to get, him 53. Both, and, are, teachers 54. instead of 55.It’s easy, to draw第三节:根据所给中文完成句子。
(10%)56. lost his memory, accident 57. keep in touch with 58. is worth reading, expensive(dear) 59. parents are delighted with 60. gets in trouble with第四节:书面表达(10%)Lin Tao is a member of our school’s Kind-Hearted Club. He is a tall boy with thick black hair. He has round cheeks, small eyes and a smiling mouth. He looks strong and healthy. He is kind-hearted and gets on well with everyone. He always gets ready to help others. For example, he often helps his classmates with the lessons, helps old people cross the road. When he takes a bus, he often gives his seat to the people in need. To protect the environment, when he is free, he goes to the park to collect rubbish with his friends. Lin Tao is a good student. We should learn from him.。