【英语】英语将来完成时提高训练及解析

初中英语现在完成时详解

现在完成时一、现在完成时构成构成：现在完成时由助动词have + 过去分词构成，助动词have 有人称和数的变化。第三人称单数用has，其余用have. 现在完成时的否定式直接在助动词后面加上not、疑问式是把助动词提到主语之前。以study 为例，其否定式、疑问式和简单回答形式如下： 1、现在完成时通常表示在说话之前已经完成的动作或存在的状态。说话人强调的是该动作或状态对现在的结果或影响。 My daughter has just gone out. 我女儿刚出去。 I’m sure we’ve met before. 我肯定我们以前见过面。 She has arrived. 她到了。 2、表示持续到现在的动作或状态，往往和包括现在在内的表示一段时间的状语连用，如recently, already, just, lately, for…, since…,yet等。如： I haven’t heard from her these days. 这些日子我没有收到她的信。 We haven’t seen you recently. 最近我们没有见到你。 They have been away for two years. 他们离开已经两年了。 She has been with us since Monday.

①for+时段 ②since+过去一个时间点（译为：自从……以来） ③since+时段+ago ④since+从句（过去时） ⑤It is+时段+since+从句（过去时） Mary has been ill?for three days. I have lived here?since 1998. 注意： since和for的区别 since后接时间点，如1993，last term, yesterday, the time I got there for后接一段时间，表示“长达多久”，如ten years, a while, two days等。3、表示短暂意义的动词如arrive, leave, borrow, buy, begin, start, die等，在完成时当中不能和表示一段时间的状语连用，因为它们表示的动作不可能持续。因此，不能说： He has come here for 2 weeks. × The old man has died for 4 months. × They have left only for 5 minutes. × 4、has gone (to),has been (to), has been (in)?的区别 Have/Has gone(to) :去了(现在不在说话现场，可能在路上和已经到) Where is your father?He has gone to Shanghai. Have/Has been (to) :去过（已不在去过的地方） My father has been to Shanghai. Have/has been in：呆了多久（还在所呆的地方） My father has been in Shanghai?for two months. /since two months ago. 5、现在完成时不能和表示过去的时间状语连用，如yesterday, last year, in 1976, two days ago, just now, when I came in，但可以和already, yet, sometimes, always, often, before, lately, recently, once, twice, ever, never等连用。不能与when连用。

(英语)高中英语一般将来时练习题

（英语）高中英语一般将来时练习题一、单项选择一般将来时 1．— What do you want for breakfast, Joe? — I think I _______ some bread and milk. A．will have B．am going to have C．had D．am having 【答案】A 【解析】试题分析：句意：--早饭你准备吃什么？--我想我想吃些面包和牛奶。因为是将要吃..用一般将来时，排除C，ABD都可以表示一般将来时，will是临时决定，be going to do是计划，打算，be doing是即将，马上做…,所以选A。考点：考查时态 2．The students have been working hard on their lessons and their efforts _____ with success in the end. A．rewarded B．were rewarded C．will reward D．will be rewarded 【答案】D 【解析】【分析】【详解】本题考查时态和语态。解题步骤：1. 确定时态：根据句尾的in the end可知，事情发生在将来，用将来时。2. 确定语态：efforts和reward是被动关系，应该使用被动语态。句意：学生们一直在刻苦学习功课，他们的努力终将会得到回报。综上，用一般将来时的被动，故选D。【点睛】一般将来时 1. 表示未来的动作或状态常用will / shall + 动词（常与表示将来的时间状语边用如tomorrow、next week等）。 2. 表示一种趋向或习惯动作。例如：We’ll die without air or water. 3. 表示趋向行为的动词如come, go, start, begin, leave等词常用进行时的形式表示将来时。 4. be going to与will / shall, be to do, be about to do用法及区别： (1)shall / will do表示未事先考虑过，即说话时临时作出的决定。 (2)be going to 表示现在打算在最近或将来要做某事，这种打算往往经过事先考虑，甚至已做了某种准备；be going to 表将来，不能用在条件状语从句的主句中；而will do则能，表意愿。例如：If it is fine, we’ll go fishing.(正确) If it is fine, we are going to go fishing.(错误) (3)be to do sth.表按计划、安排即将发生的动作，还可表示吩咐、命令、禁止，可能性等。

(英语)将来完成时练习含解析

（英语）将来完成时练习含解析一、单项选择将来完成时 1．—Oh, Mom, just a few minutes. —Hurry up, Harry, or by the time you pack your belongings, the flight _________! A．has left B．will have left C．had left D．will be leaving 【答案】B 【解析】试题分析: 考察将来完成时的用法。句意：---妈妈，等会儿。---快点，否则等你收拾好了行李，飞机就已经飞走了。将来收拾好行李时，飞机已经飞走了。将来的某个时间已经发生，用将来完成时。所以选B。考点：考察将来完成时的用法。 2．Hurry up! The concert will begin at half past eight. The performers _________ half an hour when you arrive. A．will be playing B．will have played C．are playing D．have played 【答案】B 【解析】考查时态。句意：快点！音乐会将在八点半开始。当你到达时，表演者将已经演奏半小时了。将来完成时表示将来某一时刻或将来的另一个动作之前，已经完成的动作，强调的是完成，故选B。 3． If we don't hurry up, everything ________ by the time we get to the party. A．will be eaten B．is eaten C．has been eaten D．will have been eaten 【答案】D 【解析】 D 考察时态。句义：如果我们不快点，当我们到达宴会的时候，所有的东西可能都已经被吃完了。If引导条件状语从句，从句是一般现在时，故主句要使用将来时，且由by the time可知，应该使用完成时态。故D正确。 4．Do you know Tom,the manager of that company? -Of course,I know him,By next month,I______him for 10 years.

英语一般将来时用法总结(完整)

英语一般将来时用法总结(完整) 一、单项选择一般将来时 1．Peace is necessary to all. After all, it is the United States and China, as the two largest economies in the world, that ________ most from a peaceful and stable Asia-Pacific. A．are benefited B．will benefit C．will be benefited D．had benefited 【答案】B 【解析】试题分析：根据语境“美国和中国将受益于一个和平稳定的亚太地区”可知该句要用一般将来时，故选B。考点：考查时态 2．--- I’d like a mountain bike which ____ well? --- Will this one _____? A．rides; work B．rides; do C．is ridden; do D．is ridden; work 【答案】B 【解析】试题分析：考查主动形式表示被动含义用法。一些不及物动词与副词连用，表示主语的特征。如wash well，write well等；用主动形式表示被动的含义。本句中的ride well指自行车好骑；第二空的do表示行。句意：—我想买一辆很好骑的山地车。—这个行吗？根据句意说明B正确。考点：考查主动形式表示被动含义的用法。点评：。一些不及物动词与副词连用，表示主语的特征。如wash well，write well等；用主动形式表示被动的含义。 3．It every day so far this month. I can't tell you if it tomorrow. A．rained; rains B．is raining; shall rain C．has been raining; rains D．has rained; will rain 【答案】D 【解析】试题分析：本题第一空应该使用现在完成式，关键词是后面的时间状语so far(到目前为止)，so far通常都是和现在完成时连用。第二空是一个if引导的宾语从句，并非if引导的条件句，在这个宾语从句中，时间状语是tomorrow，这是一个将来时的时间状语，故该宾语从句使用将来时。句义：这个月到现在为止天天都在下雨，所以我无法告诉你明天是否还要要下雨。故D正确。考点：考察时态 4．What you learn today ______ of practical use when you hunt for a job. A．is proved B．proves C．will be proved D．will prove

一般将来时时态用法讲解

一般将来时时态用法讲解Last revision on 21 December 2020

一般将来时时态 1. 一般将来时的定义一般将来时表示在现在看来即将要发生的动作或存在的状态。常用时间副词tomorrow, soon或短语next year / week / month, in a few days, in the future, sometime 做状语。如： What will you do this afternoon 你今天下午干什么 We will have a meeting tomorrow. 我们明天要开会。 He is going to study abroad（到国外） next year. 明年他要出国学习。 2. 一般将来时的结构及应用 (1) shall / will + 动词原形。表示即将发生的动作或存在的状态。特别是表示客观性的事情或在某条件下要发生的事情，只能用此结构。如： What shall we do if he doesn’t come 如果他不来，我们该怎么办 Will you be free this evening 今天晚上有空吗 I think he will tell us the truth（真相）。我想他会告诉我们真实情况的。 (2) be going to + 动词原形。表示已经计划或安排好了的事情，也可表示有迹象表明肯定要发生的事情。如： We are going to have a meeting to discuss （讨论）the matter this evening. 今天晚上开会讨论这件事情。 Look at the black clouds over there. I think it is going to rain soon. 看一看那边的乌云，我想天要下雨了。 There is going to be an English evening this week. 本周要举行一个英语晚会。 (3) be +现在分词。表示即将发生的动作或存在的状态。这个句型中动词主要是瞬间动词：come, go, leave, arrive, begin, start, stop, close, open, die, join, borrow, buy等。如： Go ahead, and I’m coming. 走前面一点吧，我就来。 The dog is dying. 那条狗要死了。 Hurry up. The shop is closing. 快点，商店就要关门了。 (4) 一般现在时。表示一种严格按照计划进行的动作。比方说，上课、飞机起飞、火车离站等。如：

初中英语现在完成时专题训练答案

初中英语现在完成时专题训练答案一、初中英语现在完成时 1．He has studied in our school __________. A. since five years B. for five years C. for five years ago D. in five years 【答案】B 【解析】【分析】句意：他已经在我们学校学习五年了。has studied是现在完成时，和for+段时间连用，since+过去时间和现在完成时连用，in+段时间和一般将来时连用，故选B。【点评】考查时间状语。根据句意选出正确的时间状语。 2．—How do you like Beijing, Miss Read? —I've no idea. I _____ there. A. have gone B. have been C. haven't been D. haven't gone 【答案】 C 【解析】【分析】句意：---你觉得北京怎么样，瑞得小姐？---我不知道，我没有去过那儿。短语：have been to去过某地（已经返回）；have gone to去了某地（尚未返回），根据句意，故答案为C。【点评】考查短语辨析，区分have been to与have gone to，理解句子，根据语境判断答案。 3．I scared of dogs ever since a dog hurt me when I was five years old. A. will be B. was C. have been D. would be 【答案】 C 【解析】【分析】由since引导的从句可知主句应用现在完成时，故答案为C。句意是：自从我五岁时被狗伤过之后我就一直怕狗。【点评】本题考查现在完成时的用法。 4．—How do you like Treasure Island，Lucy？ —It's so exciting that I _______ it twice． A. am reading B. have read C. was reading D. had read 【答案】B 【解析】【分析】句意：——露西，你认为《金银岛》怎么样？——它是如此令人激动以至于我读了两次。根据twice可知已经发生了，故此处用现在完成时，故为have read，故选B。【点评】此题考查现在完成时的用法。 5．—They say there is a new restaurant near here.

高中英语一般将来时与过去将来时习题

选择填空 1. —What did your son say in the letter —He told me that he ______ the Disney World the next day. A. will visit B. has visited C. is going to visit D. would visit 2. I hoped Tina ______ to my birthday party on time the next Wednesday. A. to come B. is coming C. will come D. was coming 3. Father said that he ______ me to Beijing the next year. A. took B. would take C. takes D. will take 4. We were not sure whether they ______ more vegetables. A. are going to grow B. were going to grow C. will grow D. have grown

5. She ______ to work when the telephone rang. A. is going B. will go C. was about to go D. is to go 6. - The plane is leaving right now, but Jim hasn't arrived yet. - Well, he said he _____here on time. A came B would come C can be D will be 7. As soon as the baby saw her mother, she _____. A was going to cry B cryed C began to cry D was crying 8. Li Ming said he _____happy if Brian_____to China next month. A as; come B was; would come C would be; came D will be; come 9. Jenny said she _____her holiday in China. A spent B would spent C was going to spent D would spend 10. ---Alice, why didn’t you come yesterday ---I ___, but I had an unexpected visitor.

最新新概念二：一般将来时-将来进行时-将来完成时练习

时态1 一般将来时概念表在将来某个时间会发生的动作或情况。常和tomorrow, next year, in 2008等表示将来的时间状语连用，其表现形式多达5种。构成will/shall + do, be to do, be about to do, be going to do, 例句They will arrive at the small village tomorrow. I am going to do my homework this evening. He is to fail 备注 1. 一般将来时总是用在一些时间状语从句或条件状语从句的主句中： We will begin our class as soon as the teacher comes.（主句用一般将来时，从句中一定要用一般现在时替代一般将来时。） 2. 某些移动性动词或趋向动词如leave, start, go ,arrive, come, stay，finish等用进行时可表示将来意义。如： I am just finishing my work, and it won’t take lon g. I am leaving for Beijing tomorrow. 3. “祈使句+ and/or + 句子”，这种结构中and后面的句子谓语用一般将来时，由于祈使句具有假设条件意义，后一分句在这一条件下要产生的结果，所以要用将来时。如： Let’s keep to the point or we will never reach any decisions. Use your head and you will find a way. 4. “am (is, are) going to + 动词原形”，表示已经决定或安排要做的事或表示有某迹象表明必然或很可能发生的事情，“am (is, are) about to + 动词原形”表示按照预定计划或打算准备着手进行的动作，但be about to do不可与段时间状语连用。“am (is, are) to + 动词原形”表示必须、必然或计划将要做的事，或注定要发生的事情，而“will + 动词原形” 而后者表示“临时决定去做某事”。如： He is going to attend the meeting. She is about to go to the dinner party. Look at these clouds. It’s going to rain. We are to succeed. 时态2 将来进行时概念表将来某个时间正在发生的动作，或按计划一定会发生的事情构成will be doing 例句I’ll be doing my homework this time tomorrow. The President will be meeting the foreign delegation at the airport. 备注将来完成时指将来某一时刻已完成的动作，用于将来完成时的时间状语如下：by the time+从句；by the end of + 将来时间的名词；by+将来时间名词等，如： By the time Jane gets home, her aunt will have left for London to attend a meeting. 时态3 将来完成时概念表在将来某时刻之前业已完成的事情，时间状语非常明显构成will have done 例句By the end of next month, he will have traveled 1000 miles on foot. I will have eaten up my meal before she comes back. 备注 1. 常用的时间状语一般用by+将来的时间，如：by the end of this year, by 8 o’clock this evening, by March next year以及由by the time…, before或when等引导的副词从句，如： By the time you reach the station, the train will have left. By next Tuesday, I will have got ready for the exams. 2. 在时间和条件状语从句中，将来完成时则由现在完成时表示，如： The children will do their homework the moment they have arrived back from school.

【英语】英语语法一般将来时归纳总结

【英语】英语语法一般将来时归纳总结一、单项选择一般将来时 1． -- How many people are expected to come to your party tomorrow afternoon? -- I send out thirty invitations but one third _____. A．didn’t show up B．won’t show up C．hadn’t showed up D．doesn’t show up 【答案】B 【解析】试题分析：考查时态。根据语境及时间状语tomorrow afternoon可知用一般将来时。句意：——期望有多少人来参加你明天的宴会？——我送出了30份邀请，但三分之一将不会出现。故B正确。考点：考查时态 2．Half the world’s population ______ water shortages within 15 years according to the World Bank, just one of many recent alarming reports on the world’s fresh wate r supply. A．are suffering B．have been suffered C．will suffer D．were suffered 【答案】C 【解析】试题分析：根据时间状语within 15 years，故用一般将来时。考点：时态考查题点评：通过时间状语，上下句意思和具体语境来确定时态。 3．As your spoken English gets better, so ___ your written English. A．will B．do C．is D．has 【答案】A 【解析】试题分析：考查倒装句和时态：第一空是倒装句的肯定形式：So + 助动词/情态动词/be动词+ 主语，表示“主语和前面句子的主语一样，做同样的事”，解释为“主语也……。”第二个点考查主将从现，所以助动词要使用will/shall。句意：随着你英语口语的好转，你的书面语也会好起来的。选A。考点：考查倒装句和时态 4． - Will you be available at three o'clock tomorrow afternoon? - No. I ______ a lecture then. A．are attending B．will have attended C．will attend D．will be attending 【答案】D 【解析】试题分析：考查动词时态。题意：“明天下午3点你有空吗？”“没空。我要听一个报告。”答句说的是未来某个时间点正在进行的动作，所以要用将来进行时态。D项正确。

(完整版)初中英语现在完成时专项练习题及答案

一、单项选择。 1、Both his parents look sad . Maybe they what's happened to him . Ａ. knew Ｂ. have known Ｃ. must know Ｄ.will know 2、He has been to Shanghai , has he ? Ａ. already Ｂ.never Ｃ.ever Ｄ. still 3、Have you met Mr Li ？Ａ. just Ｂ. ago Ｃ.before Ｄ. a moment ago 4、The famous writer one new book in the past two years Ａ. is writing Ｂ.was writing Ｃ.wrote Ｄ.has written 5、—Our country a lot so far . —Yes . I hope it will be even . Ａ. has changed ; well Ｂ. changed ; good Ｃ. has changed ; better Ｄ. changed ; better 6、Zhao Lan already in this school for two years . Ａ. was ; studying Ｂ. will ; study Ｃ. has ; studied Ｄ. are ; studying 7、We Xiao Li since she was a little girl . Ａ. know Ｂ. had known Ｃ. have known Ｄ. knew 8、Harry Potter is a very nice film .I it twice . Ａ. will see Ｂ. have seen Ｃ. saw Ｄ.see 9、—These farmers have been to the United States . —Really ? When there ? Ａ. will they go Ｂ. did they go Ｃ. do they go Ｄ. have they gone 10、—you your homework yet ? —Yes . I it a moment ago . Ａ. Did ; do ; finished Ｂ. Have ; done ; finished Ｃ. Have ; done ; have finished Ｄ. will ; do ; finish 11、His father the Party since 1978 . Ａ. joined Ｂ. has joined Ｃ. was in Ｄ. has been in 12、—Do you know him well ? —Sure .We friends since ten years ago . Ａ. were Ｂ. have been Ｃ. have become Ｄ. have made 13、—How long have you here ? —About two months . Ａ. been Ｂ. gone Ｃ. come Ｄ. arrived 14、Hurry up! The play for ten minutes . Ａ. has begun Ｂ. had begun Ｃ. has been onＤ. began 15、It ten years since he left the army .

将来完成时与将来进行时与一般将来时区别

将来完成时与将来进行时与一般将来时区别将来完成时 1)构成will/shall+have+p.p. 2)概念 a.状态完成：表示某事继续到将来某一时为止一直有的状态。 b.动作完成：表示将来某一时或另一个将来的动作之前，已经完成的动作或已获得的经验。将来完成时用来表示在将来某一时间以前已经完成或一直持续的动作。经常与before+将来时间或by+将来时间连用，也可与before或by the time引导的现在时的从句连用。如： He will have gained his pilot's license before his next birthday .他下个生日前会拿到飞行证的。 You will have received an invitation to the wedding as well.你肯定会收到参加婚宴的邀请的。 They will have been married for20years by then. You will have reached Shanghai by this time tomorrow. 将来进行时 1)概念：表示将来某时进行的状态或动作，或按预测将来会发生的事情。 She'll be coming soon. I'll be meeting him sometime in the future.

注意：将来进行时不用于表示"意志"，不能说I'll be having a talk with her. 2）常用的时间状语 Soon,tomorrow,this evening，on Sunday,by this time，tomorrow,in two days,tomorrow evening By this time tomorrow,I'll be lying on the beach. 一般将来时 1)shall用于第一人称，常被will所代替。 will在陈述句中用于各人称，在争求意见时常用于第二人称。Which paragraph shall I read first. Will you be at home at seven this evening? 2)be going to+不定式，表示将来。 a.主语的意图，即将做某事。 What are you going to do tomorrow? b.计划，安排要发生的事。 The play is going to be produced next month。 c.有迹象要发生的事 Look at the dark clouds,there is going to be a storm. 3)be+不定式表将来，按计划或正式安排将发生的事。 We are to discuss the report next Saturday.

一般将来时时态练习题

用所给词的适当形式填空 1. What does your brother want _____(be) when he grows up? 2. They ______________(buy) a big house next year. 3. Liu Mei _____________(live) in Hainan when she finishes college. 4. Where ___ you ____________(work) after you graduate (毕业)? Ⅱ. 句型转换 1. Kate often takes Chinese lessons. (用next school year改写句子) Kate __ _____ __ ____ Chinese lessons next school year. 2. The Browns are going to move to China. (改为否定句) The Browns ______ _____ __ _____ to China. 3. They are going to visit the Great Wall next summer vacation. (改为一般疑问句) ____ they _____ __ ____ the Great Wall next summer vacation? 4. She is going to work with Jim. (对画线部分提问) _____ __ she going to ___? Ⅰ. 用所给词的适当形式填空 1. What do you want (do)when you leave school? 2. The man over there is a famous (science). 3. In my heart, Wu Bin, a bus (drive), is a real hero(英雄). 4. We (visit)the Great Wall next Sunday. 5. —Do you know Li Na? —Yes. She is a well-known tennis (play). 完成句子 1. 当你上完中学时, 你打算做什么? What are you going to do when you ______ _______ _______? 2. 你想成为一名足球运动员吗? Do you ______ ____ ____ a soccer player? 3. 她爸爸经常写文章并把它们寄给杂志社。 Her father often ______ ________ and ______ _______ to magazines. 4. 你打算去哪里工作? _______ are you _______ ____ ______? 5. 离开的时候你必须确保把门锁上。 You should ______ _______ that you lock the door when you leave.

【初中英语】现在完成时知识点总结

【初中英语】现在完成时知识点总结一、初中英语现在完成时 1．The small shop ________ for several years. A. opened B. has been opened C. has opened D. has been open 【答案】 D 【解析】【分析】open是非延续性动词，和表示一段时间的时间状语连用必须转化为延续性动词be open.根据句意，本句应用现在完成时态，故选D。【点评】考查open转化为be open, be open里的open是形容词，不能加ed.. 2．The volunteers ________ a lot of help to the old and the young since 2010． A. offered B. have offered C. are offering D. will offer 【答案】 B 【解析】【分析】考查时态．句意"自2010以来，志愿者们向老人和青年提供了大量的帮助．"．A过去时．B现在完成时态．C现在进行时态．D一般将来时态．since+点时间通常用于现在完成时态，结构是have/has+动词的过去分词，主语是volunteers复数，用助动词have．offer的过去分词是offered．答案是B． 3．I am surprised at the new look of my hometown，for it _____ a lot over the years． A. changed B. changes C. will change D. has changed 【答案】 D 【解析】【分析】我对我的家乡的新面貌感到惊讶，因为这几年改变了很多，结合over the years可知表达的动作发生在过去，对现在造成一定的影响，故用现在完成时have/has+过去分词，主语it，故has，故答案是D． 4．I scared of dogs ever since a dog hurt me when I was five years old. A. will be B. was C. have been D. would be 【答案】 C 【解析】【分析】由since引导的从句可知主句应用现在完成时，故答案为C。句意是：自从我五岁时被狗伤过之后我就一直怕狗。【点评】本题考查现在完成时的用法。

英语语法-将来完成时

英语语法-将来完成时将来完成时用来表示在将来某一时间以前已经完成或一直持续的动作。经常与before+将来时间或by+将来时间连用，也可与before 或by the time引导的现在时的从句连用。构成will/shall+have+完成式用于第一人称，will+have+完成式用于其他人称。推荐信息英语四级写作句型一般将来时英语四级写作句型过去将来时英语四级写作句型六大成分英语的句子四级写作必备句型直接引语转换间接引语 a.状态完成：表示某事继续到将来某一时为止一直有的状态。 b.动作完成：表示将来某一时或另一个将来的动作之前，已经完成的动作或已获得的经验。 They will have been married for 20 years by then. You will have reached Shanghai by this time tomorrow.将来完成时的构成将来完成时的构成是由"shall/will + have +过去分词"构成的。 Before long he will have forgotten all about the matter. 不久他就会全然忘记这件事的。 He is somebody now. He will not have remembered his old classmates. 他现在是一个有身份的人了，他可能不会记得老同学了。 Will you have known Kevin for 10 years next month? 到下个月你理解凯文该有10年了吧？

将来完成时的用法 ①表示在将来某一时间之前已完成的动作，并往往对将来某一时间产生影响。 We shall have learned 12 units by the end of this term. 到这个学期末，我们将学完12个单元。 By the time you get home I will have cleaned the house from top to bottom. 你到家之前我将把房子彻底打扫一遍。 ②表示推测，相当于"must have done"结构。 You will have heard of this, I guess. 我想你已经听说过这件事了。 I am sure he will have got the information. 我相信他一定得到了这个信息 ③表示某种状态一直持续到说话人所提及的时间 we will have been married a year on june 25th. 到6月25日我们俩结婚就满1年了将来完成时用来表示在将来某一时间以前已经完成或一直持续的动作。经常与before+将来时间或by+将来时间连用，也可与before 或by the time引导的现在时的从句连用。