高二英语选修8Unit3全单元学案

Unit 3 Inventors and Inventions导学案I Word study
【教师寄语】
A thousand-mile journey is started by taking the first step.(千里之行，始于足下)
【学习目标】1.To grasp the main words of this unit.
2. To find out the useful phrases and recite them.
【自主学习】Self-previewing
1.学习课本第三单元新单词。

2.根据所给词性和汉语意思写出单词
1. __________ n.专利证书；专利权；v.获得专利权
2. _______ vt.&vi.显示……的差别;使……有所不同;辨别→ _______ adj.卓著的;著名的;高贵的
3. __________adj.突然的；意外的__________ adv.突然地；唐突地
4. __________ adj.便利的；方便的；就近的→_________n.便利, 方便→_________adv. 便利地
5. __________ n. 预料；期待；期望→__________vt.期待；预期；盼望
6. __________ vt.&vi.轻打；轻拍；轻敲；n.轻轻地敲击（声）；（水）龙头
7. __________ n.金属丝；电线→__________ adj.无线的
8. __________n. （水或气）流；电流；adj.现在的；当前的→_________adv.普遍地；通常地
9. __________adj. 稳固的；稳定的；安定的→__________n. 稳定性
10. __________ vt.联想；联系；n.同伴；伙伴→__________ n. 联系；协会
11. __________adj.实际的；实践的；实用的→__________adv. 实际上；事实上
12. __________adj.宽大的；仁慈的；慈悲的→__________n. 怜悯；仁慈；宽恕
【合作探究】Cooperative exploring
3.根据汉语词义写出单词
1. call________ 给……打电话
2. now and ________偶尔；有时
3. set ________开始；着手
4. dive ________迅速把手伸入；一心投入
5. set ________(to do)开始（做）
6. hang ________不挂断；紧紧握住；稍等
7 ________ ________ order次序颠倒；发生故障
8. get ________设法联系上（尤指打通电话）；（设法）做完；通过
9. ring ________回复电话10. ring ________挂断电话
11. ________ case （以防）万一12. ________ truth 的确；事实上
4. 单词拼写
1. I’m sorry, but I don’t know there is an_______(突然的)change of plan.
2. As________(预料), the sales manager gave in his notice at work today.
3. It’s our_________(期望)that you will do well.
4. We should try our best to put the enemy in a _______(被动的)position.
5. As we all know, newspapers influence the________(潮流)of thought.
6. Your books and magazines are almost in a m______; go and put them in order.
7. The football club c________ arranges all the matches.
8. I have heard two v________ of the accident.
9. Illness is a v________ excuse for being absent from work.
10. She t________ me on the shoulder, but I didn’t feel it.
1. It turned out that the newcomer was _______ a spy.
2. I won’t _______ my brother unless something unexpected happens.
3. Please _______. I will go and get her.
4. Our freezer is _________ again. We’d better buy a new one instead of repairing it.
5. The police ___________ investigate the cause of the fire.
6. Please take your credit card with you ________ your money is not enough.
7. She_________ her bag and took out a few coins.
8. The line is engaged; I cannot ________ to his office.
9. I must _________ now because I will go to a meeting.
10.________, I visit my grandpa and grandma in the country.
6. 反馈练习选择最佳选项并填空。

1）As I grew up in a small town at the foot of a mountain, the visit to the village ______ scenes of my childhood. A. called up B. called for C. called on D. called in
2). We get along quite well though there are quarrels between us _________.
A. now and then
B. here and there
C. at one time
D. up and down
3). Let’s _________our personal feelings for now, and get to our business.
A. set up
B. set off
C. set about
D. set aside
4). He told me that in the following days there were other changes, even more_________.
A. abrupt
B. changeable
C. suitable
D. typical
5). His parents’ greatest ________ is that he could be accepted by the top university.
A. means
B. majority
C. mixture
D. expectation
6).The young man ________his pocket to make sure his wallet was still there.
A. went into
B. got into
C. looked for
D. dived into
7). I had to _________because someone else wanted to use the phone.
A. hang on
B. keep up
C. hang up
D. ring up
8). Hardly could he _________this amount of work in such a short time.
A. get through
B. get off
C. get into
D. get down
Unit 3 Inventors and Inventions导学案II Reading
【教师寄语】Nothing seeks, nothing finds. (所求则无所获。

)
【学习目标】1.To grasp the main idea of the text.
2. To find out the difficult phrases and then recite them.
【学习过程】Learning Procedures
【自主学习】
1. Read the text carefully and choose the best answer.
1. According to the text, which of the following inventions may get a patent?
A. A new star discovered by a scientist.
B. A new novel written by Huo Da.
C. A new way to make dirty water clean.
D. A new kind of grass found in a mountain which can be used as a medicine.
2. Which of the following is TRUE according to the text?
A. In my first attempt, the snakes were as active as before.
B. The snakes were not sleepy at all in my second attempt.
C. I killed all the snakes after I collected them.
D. Ice-cubes were used in the three attempts.
3. The purpose in writing this text is ________________.
A. to show us how to trap the snakes but not to kill them
B. to tell people how to apply for a patent of the writer's new idea
C. to introduce the writer's new idea of trapping the snakes and her application for a patent
D. to tell the readers how to get a new idea and make it a patent
4. The biggest advantage of the writer's new idea is that:
A. it makes the snakes move slowly
B. it makes the snakes hardly bite us
C. it is easier for us to kill the snakes without hurting ourselves
D. it is easier for us to catch the snakes without killing them
5. What instruments were used for catching the snakes?
A. a bowl, ice-cubes, male perfume
B. a bowl, a bucket, female perfume
C. a small net, ice-cubes, a bucket
D. a small net, a bucket, powders
6. Which statement is true according to the text?
A. The snakes were so sleepy in the second attempt that they couldn't bite the writer at all.
B. Your product must be different from everybody else's if you want to receive a patent.
C. The writer decided to send her invention to the patent office the moment she succeeded in
catching the snakes.
D. If an application for your product proves to be valid, you can get a patent immediately.
2. Here are some stages before they can have their invention approved, please out them in the suitable order
1. A. Deciding on the invention
2. B. Testing the solution
3. C. Finding a problem
4. D. Applying for a patent
5. E. Doing research
6. F. Thinking of a creative solution
3. Read and answer the questions.
1). What was the mother upset about?
_________________________________________________________________________________ 2). Why was the writer happy to help her mother?
_________________________________________________________________________________ 3). Why did cooling make the snakes less active ?
_________________________________________________________________________________ 4. Make a summary within 30 words
The writer _______ a harmless way to _________ the snakes . She trapped the snakes by making them _____ and ______. She tried _______ solutions and __________. She wanted to apply for a __________ for it.
Exploring: Work in groups and try to translate and analyze the following sentences, please pay more attention to the Black part and summarize usages.
1). Here was a chance for me to distinguish myself by inventing something merciful that would catch snakes but not hurt them.
Translation: ______________________________________________________________________ 在本句中，主句以here开头，构成______, 以加强语气；that引导_____从句，修饰先行词_______.
2) The first thing I did was to see if there were any products that might help me, but there only seemed to be powders designed to kill snakes.
Translation: ______________________________________________________________________ 在本句中，划线部分用来做___语，前面两个是______从句，designed是_____分词作定语，表被动。

If引导的是__________从句，but there only seemed是___________句型。

3）Pressed by my friends and relations, I decided to seize the opportunity to get recognition for my successful idea by sending my invention to the patent office.
Translation: ______________________________________________________________________ 在本句中，划线部分是_____分词做___语，与逻辑主语I 是_____关系。

4）Only after you have had that recognition can you say that you are truly an inventor. Translation: ___________________________________. Only +状语放在句首，主句使用_____倒装，也就是把____动词、动词、动词放在主语之前。

在本句中，after引导的是状语从句。

5) This was in the expectation that the snakes would bite again.
译：____________________________________________________________________________.
(1) 本句中that从句是一个________________从句，是expectation的_______。

Expectation 为名词意为预料；期待。

例如：今晚预计无雪。

译：_____________________________________________________________________________. Find out the sentences in the text which have similar meanings with the following ones.
(1) You can’t say you are truly an inventor unless you had that recognition.
________________________________________________________________________________.
(2)You’ll know i f I receive a patent by check my bank balance.
________________________________________________________________________________.
5) Change the sentences according to the suggestion.
(1)The criteria are very strict. It is not easy for new ideas to be accepted.(用so……that连成句子) _________________________________________________________________________________ (2)Nor will you receive a patent until a research has been made to find out your product really is different from everybody else’s.(改成强调句式)
________________________________________________________________________________ Summing up
1. Summary of the text
The problem of the snakes in our yard 1.________us all the time. My mother wanted me to get 2.________of the snakes. I thought of three possible 3._______to catch them. Firstly, removing their 4.________; secondly, attracting them into5.________; and thirdly cooling them so that they would become 6.________and could be easily caught. But all these 7._______failed. So I had to8._______ my plan. My last attempt proved to be successful. I carried in my hand a small net used for 9.________fish. All went well according to plan.
The snakes were caught and the next day they were all 10._______ back into the wild. 11._____ by my friends and relations, I decided to get my invention 12.________by the patent office. I have filled in the form and 13.________ my patent application 14.________the Patent Office. I am expecting success enthusiastically now!
2. Important words and phrases
(1) 专利证书；专利权___________ (2) 偶尔；有时_______________
(3) 使自己出名_________________ (4) 抓住机会________________
(5) 银行结余金额_____________
3. Sentence Patterns (句子结构感悟)
(1) 但是看来只有一种毒杀蛇的药粉。

(2) 经过一番研究准备之后，我决定采用三种可能的办法。

(3) 只有你得到这种承认，你才可以说是一个真正的发明家。

(4)（评定）专利标准非常严格，除非新的想法真是新颖的，否则很难被接受。

Unit 3 Inventors and Inventions导学案III Using Language
【教师寄语】Behind bad luck comes good luck. (塞翁失马焉知非福)
【学习目标】1. Learn about the whole texts and get the main idea.
2. Master the useful words and expressions.
【学习过程】Learning Procedures
Before class
Task 1 Vocabulary
Preview the new words and phrases of this text.
1.___________ n.额头
2. n.稻草；饮料吸管
3. n.重要性
4. n. / adj. 流；电流/ 现在的；当前的；
5. adj.稳定的；稳固的
6. _________________开始（做）
7. _________________ 迅速把手伸入；一心投入8 . ________________的确，事实上
In class:
Step1 Check-up and lead in
1. Check the answers of Task 1
2. How much do you know of Alexander Graham Bell. Guess which invention he invented. (still used today)
Step 2 Fast reading
Read the passage quickly and find out the main idea of the text.
________________________________________________________________________________ Step 3 Careful reading
1. Read again and find the answers to the following questions.
1) How did curiosity make Alexander Graham Bell into a great inventor?
_______________________________________________________________________________ 2) What did he think was the key to his success as an inventor?
_______________________________________________________________________________ 3) Why will he always be known as the inventor of the telephone?
______________________________________________________________________________ 2. Read the text carefully and choose the correct answer to complete each sentence.
1). Bell invented the _________ by chance according to the text.
A. Morse code
B. telegraph
C. telephone
D. tetrahedron
2). Which statement is true according to the text?
A. Bell made a contribution to the deaf education.
B. Bell invented the telephone for the deaf.
C. Bell thought you shouldn’t think too much about something you had never seen before.
D. Bell invented a lot of flying machines while searching for a kite to carry a man into the air.
3). According to the text, Bell got such great achievement thanks to__________.
A. a straw joined to a de af man’s ear
B. the exploring around problems
C. a moving electrical current
D. his excellent assistant Watson
4). We can infer from the text that_________.
A. doing research in telegraph helped Bell greatly in inventing the telephone
B. Bell was given the patent after he succeeded in sending the first telephone message
C. in order to make the bridges stronger Bell discovered telephone
D. Bell discovered so many practical solutions that he must be a millionaire
Step 4 Exploring study
Read the text again, find out the sentences and analyze them.
1. He found that by pressing his lips against his mother’s forehead, he could make the bones move in such a way she could understand what he was saying. (P25 L4-6)
翻译：________________________________________________________________________ 本句是一个复合句，that 引导________从句; she could understand what he was saying是以_________为先行词的_________从句。

注意：the way 做先行词引导__________时引导词有三种情况，1)in which 2) that 3)不填如：I don’t appreciate the way that /in which /-- you deal with such a problem.翻译：
______________________________________________________________________________ 2. It was this exploring around problems that led to his most famous invention—the telephone in 1876. (P25 L14)
翻译：__________________________________________________________________________ 本句为_______句式，该句式结构为___________________.
比较：The patent was given in 1876, but it was not until five days later that Bell sent the first telephone message to his assistant, Watson. (P25 L28)
由until引出的短语或者从句，所用的强调句型是__________________________.
注意: 在强调结构中不能用which代替其中的that,当被强调部分是人时可用who, whom, that. Step 5 Language study 词语学习与运用
1. set out.
【归纳总结】set out有两层意思：set out to do…意为___ _；set out for…意为_________。

【知识链接】set about 开始做某事；set against使与（某人）对立；set aside（为某种目的）留出，拨出；set back延缓，阻碍；set down写下，制定，下车；set off 启程，动身，引起，激发；set up（公司、机构等）建立，成立
【即景活用】
1) He clearing up after the party a proper.
2) Try to _______________ at least an hour each day for learning new vocabulary..
3) We packed our rucksacks and _____________ the hills.
2. Although he will always be known for his invention of the telephone, he was in truth a continuing searcher after practical solutions to improve the quality of everybody’s life.( P26，L2-3)
翻译：____________________________________________________________________________ 2. in truth
【归纳总结】in truth意思为，相当于。

【即景活用】The ugly frog was __________a handsome prince.
3. a c ontinuing search
【归纳总结】句中continuing是动词-ing形式做定语。

【即景活用】Everyone present was deeply__________ by the __________story.
A. moved; moved
B. moving; moving
C. moving; moved
D. moved; moving After class
达标测试I. 单词拼写
1. Most of the old are interested in c_______ events.
2. The real __________(重要) of this new law is the protection it gives to female workers.
3. He is wearing a p___________ uniform which is comfortable and doesn’t show the dirt. .
4. This illness makes a m________ of my holiday plans.
5. Norman is a bit neurotic(神经质的), but his wife is a very s____________ person.
II.
2. He ____________ his pocket and pulled out a quarter.
3. At dawn, they ____________ to get ready for the work of the day.
4. They live miles off the ____________.
5. He was ____________ the greatest artist of them all.
III. 单项填空
1. He ______the bag and brought out two red apples.
A. put into
B. dragged into
C. dived into
D. caught into
2. He ______his career and made a great contribution to our country.
A. dived himself into
B. devoted himself to
C. dived into
D. devoted to
3. At dawn, they set ______to get ready for the work of the day.
A. off
B. about
C. out
D. in
4. They set ______at about 8 o’clock.
A. about to work
B. about to working
C. about working
D. out work
5. They _____the mountain at noon.
A. set off to
B. set out to
C. set out for
D. set off in
6. 1.When we plan our vacation, mother often offers_____ suggestions.
A. careful
B. practical
C. effective
D. acceptable
7. It is believed that if a book is _______, it will surely_____ the reader.
A. interested; interest
B. interesting; be interested
C. interested; be interesting
D. interesting; interest
VI. 翻译句子
1. 这确实是个奇迹。

(in truth) ________________________________________________
2. 就是在公园里你遇到了我。

(It was…that…) __________________________________
3. 我的胃不舒服,得立刻去看医生。

(out of order) ________________________________
4. 他跳到水中,救起那快要溺死的小孩.(dive into) ________________________________
Unit 3 Inventors and Inventions导学案IV Grammar
【教师寄语】All things in their being are good for something. (天生我才必有用)
【学习目标】掌握过去分词做定语，表语和宾语补足语(语法归纳见《金榜P44》)
【课堂演练】I. 单项选择
1) Most of the artists to the party were from South Africa.
A. invited
B. to invite
C. being invited
D. had been invited
2) The first text books for teaching English as a foreign language came out in the 16th century. A. having written B. to be written C. being written D. written
3) The Olympic games, in 776 BC, didn't include women players until 1912.
A. first playing
B. to be first played
C. first played
D. to be first playing
4) Prices of daily foods through a computer can be lower than prices in stores. (2002年全国春）A. are bought B. bought C. been bought D. buying
5) Mr. Smith,_______ of the speech, started to read a _______ novel. (2003 北京春)
A. tired, boring
B. tiring, bored
C. tired, bored
D. tiring, boring
6) Cleaning women in big cities usually get _______ by the hour.
A. pay
B. paying
C. paid
D. to pay
7) As we joined the big crowd I got _________ from my friends.
A. separated
B. spared
C. lost
D. missed
8) The pilot asked all the passengers on board to remain _______as the plane was making a landing.
A. seat
B. seating
C. seated
D. to be seating
9) --- Good morning. Can I help you? --- I’d like to have this package _________, madam.
A. be weighed
B. to be weighed
C. to weigh
D. weighed
10) The missing boys were last seen ________ near the river.
A. playing
B. to be playing
C. play
D. played
11) The managers discussed the plan that they would like to see ___ the next year. (NMET2000)
A. carry out
B. carrying out
C. carried out
D. to carry out
12) Mrs. Brown was much disappointed to see the washing machine she had had ___ went wrong again. A. it B. it repaired C. repaired D. to be repaired
13）The repairs cost a lot, but it’s money well__________.
A. to spend
B. spent
C. being spent
D. spending
14) The prize of the game show is $30,000 and an all expenses ______vacation to China.
A. paying
B. paid
C. to be paid
D. being paid
15) A good story does not necessarily have to have a happy ending, but the reader must not to be left_________. A. unsatisfied B. unsatisfying C. to be unsatisfying D. being unsatisfied
16) He is very popular among his students as he always tries to make them ______in his lectures.
A. interested
B. interesting
C. interest
D. to interest
II. 用所给词的适当形式填空。

1. When I arrived home one day, I found her ______ (seat) under the tall tree.
2. You can improve your mind by _______ (read) literary classics.
3. In order to make himself _____ (hear), he raised his voice a little bit.
4. The pool, _______ (cover) an area of 300 square meters, is big enough for you to enjoy.
5. The children will get ________ (confuse) if asked to learn too much at a time.
6. Do you like the book _____ (make) up of untrue stories?
7. Don’t keep the visitor ______ (wait) for such a long time.
8. Most of my classmates know that I like reading books ______ (write) by Zhang Ailing.
Unit 3 Inventors and Inventions导学案V Writing Assessments
【教师寄语】Cease to struggle and you cease to live. （生命不止，奋斗不息。

）
I. Ability enhancing：单项填空从A、B、C、D四个选项中选出可以填入空白处的最佳选项。

1. _______ heavy rain, the football match will be postponed.
A. In case of
B. In case
C. In order that
D. In the case of
2. If it is quite ___________ to you, I will visit you next Friday.
A. convenient
B. fair
C. easy
D. comfortable
3.The boy tried his best to make himself ________in his _______ English.
A. understood, breaking
B. understand, broken
C. understand, breaking
D. understood, broken
4.— Who are those people with the banner?
— A group_________ itself the League for Peace.
A. Calling
B. calls
C. called
D. is called
5. You will never know how many difficulties she _______ to educate her children.
A. got across
B. got on
C. got through
D. got over
6. So difficult _______ it is to work out the problem that I decided to ask Tom for advice.
A. I did find
B. did I find
C. I have found
D. have I found
7. You should understand the traffic rule by now. You have had it _______ often enough.
A. explaining
B. to explain
C. explain
D. explained
8. — Can I do the job?
—I’m afraid not, because it ________ skill and practice.
A. calls on
B. calls out
C. calls up
D. calls for
9. The problem __________now is very important.
A. being discussed
B. discussed
C. discussing
D. to be discussed
10. I really don’t want to go to the party, but I don’t see how I can _______i t.
A. get back from
B. get out of
C. get away
D. get off
11. The computer center, ________last year, is very popular among the students in this school.
A. open
B. opening
C. having opened
D. opened
12. Snakes come near the house ________, and they seem to have made their home here.
A. for now
B. now and then
C. from now on
D. just now
13. Roses need special car ______ they can live through winter.
A. because
B. so that
C. even if
D. as
14. Once _______ to speak properly, you can make yourself attracted at many occasions.
A. educating
B. educated
C. to educate
D. to be educated
15. Only when the war was over _______ to his hometown. (01上海春)
A. did the young soldier return
B. the young soldier returned
B. returned the young soldier D. the young soldier did return
16. — I wonder if I could use your telephone.
— __________.
A. I wonder how
B. I don’t wonder
C. Sorry, it’s out of order
D. No wonder, here it is
17. The boy who got the first prize looked around him _______.
A. in delight
B. in shock
C. in surprise
D. in disappointed
18. The picture ________ on the wall is painted by my nephew.
A. having hung
B. hanging
C. hangs
D. being hung
19. It is known to all that Japanese _______ greatly _______ French in pronunciation.
A. differs / with
B. is different/ with
C. differs/ from
D. are different/ to
20. When he turned professional at the age of 11, Mike _______ to become a world champion by his coach and parents. A. expected B. was expecting C. was expected D. would be expected II. Summarizing（原精读课文缩写）根据课文内容用合适的单词填空。

I 1 a new way that would catch snakes but not harm them. the first thing I tried to do is to find powders 2___ to kill snakes. I 3 researching the habits of snakes, so I could trap them in the easiest way. 4 with these findings, I decided on three possible 5 , but failed. I had to 6 my plan.
For the second 7 , I tried to make them sleepy, but once 8 , they would bite me. So I have to think of ways to improve my design again. After my third try, I collected the 9 snakes and the next day we 10 them all back into the wild. I succeeded and felt proud. Now I had 11 in the form and filed my patent 12 with the patent office.
III. Error correcting下列各句均有一处错误, 指出并改正。

1.The match between Class 4 and Class 5 is sure to be excited.
2. Interesting in English, he listens to BBC every day.
3. How I wish I could make myself understanding fully in English!
4. We met him at the giving time and place．
5. When heard the news, she burst into laughter.
6. He was sitting in the chair, read a book.
7. The villagers had many trees planting just then.
8. Entered the room, she found the wall newly painted.
IV. Writing List functions of cell phones.
A________________________ B________________________
C________________________ D________________________
II. Do you think whether cell phones should be allowed at school?
1. Your ideas:
A____________________________________________
B____________________________________________
C____________________________________________
Words for supporters:
convenient; tool; exchange information; communicate with others;
relax our selves by…; look up words; read news;
Words for objectors:
do harm to; cheating devices; download improper messages; be addicted to; disturb;
A writing format
Part I
We had a heated discussion about/on……
Opinions are divided on the question.
Part II
(1)Some of us think that …The reason is that…….What’ more, …….besides……
(2)However/On the other hand, others have the opposite opinion.
They think that……Firstly,……secondly……thirdly……
Part III
As far as I am concerned/ In my opinion,…. For one reason,…….... For another reason…….
In a word,…….
________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ V. Translating: 翻译下文，尽量运用本单元学过的词汇及短语：
当今学生经常被鼓励在课余时间制作一些小发明或小制作。

这里有几条建议可遵循：首先你应该着手做一些试验的准备工作。

然后，可以采取几步来完成你的试验。

如果前几次尝试失败了，那也没有关系，只要你坚持做，最终肯定能够成功。

成功后最好能够把它运用到实践中，以防它根本不能工作。

一旦完成了，这些小发明必须送到专利办公室,对你的成功的主意进行申请专利。

写作过程：
（1）审题：______________________________________________________________
（2）列出相关词汇短语：__________________________________________________ ____________________________________________________________________ （3）谋篇：______________________________________________________________
（4）写作：______________________________________________________________
Unit 3 Inventors and Inventions 3 Language points(教师参考)
【教师寄语】A thousand-mile journey is started by taking the first step.(千里之行，始于足下) 【学习目标】To master the language points of the text.
【自主学习】
Language points in Reading
1. Do you know the stages every inventor must go through before they can have their invention approved?
go through
(1) 经历Most families went through a lot in the war.
(2) 通过, 成功, 成交The plan did not go through.
(3) 审阅, 检查I can’t go though the letters in an hour.
(4) 翻找, 查看Mother went through the drawer for her glasses.
(5) 穿过, 通过 A terrible noise went through the house.
2. do research on /into /in... 从事, 进行, 做研究
They are carrying out a research into the causes of cancer.
research可作可数名词和不可数名词, 有自己的单复数形式。

短语do research中research 为不可数名词。

3. call up 打电话，使......回忆起
I’ll call you up tonight (call sb. /ring sb. up )
The old photo calls up memories of my
childhood. (recall sth.)
call for 需要, 要求
call back 回电话，召唤某人回来
call in 邀请, 请来
call on/at 拜访(call on后跟人作宾语，call at后跟地点名词作宾语)
4. now and then 有时, 偶尔I see them now and then, but not often.
相关短语：
from time to time 有时，不时
(every) now and again 偶尔，有时
from now on 从现在开始, 今后
just now 刚才
since then 从那时以来
5. Here was a chance for me to distinguish myself by inventing something merciful that would catch snakes but not harm them.
这回我有机会表现一下自己了，我要发明某种仁慈的东西，既能捉住蛇，又不会伤害它们。

distinguish 辨别, 区别
I can’t di stinguish the twins, they are so alike.。