11. 动词的时态（二）

11.13 since的四种用法
　 1) since +过去一个时间点　(如具体的年、月、日期、钟点、1980, last month, half past six)。
　 I have been here since 1989.
　
　 2) since +一段时间+ ago
　 I have been here since five months ago.

　 3) since +从句　
　 Great changes have taken place since you left.
　 Considerable time has elapsed since we have been here.

　 4) It is +一段时间+ since从句
　 It is two years since I became a postgraduate student.

11.14 延续动词与瞬间动词
1) 用于完成时的区别
　　延续动词表示经验、经历； 瞬间动词表示行为的结 果，不能与表示段的时间状语连用。
　　 He has completed the work.　　他已完成了那项工作。 (表结果)
　　 I've known him since then.　　 我从那时起就认识他了。(表经历)

2)　用于till / until从句的差异
　　 延续动词用于肯定句，表示"做……直到……" 瞬间动词用于否定句，表示"到 ……，才……"
　　 He didn't come back until ten o'clock.
　　　　他到10 点才回来。
　　 He slept until ten o'clock.　　　　　
　　　　他一直睡到10点。
　
典型例题
1. You don't need to describe her. I ___ her several times.　
A. had met　B. have met　 C. met　D. meet
　 答案B. 首先本题后句强调对现在的影响，我知道她的模样，你不用描述。再次，several times告知为反复发生的动作，因此用现在完成时。

2.---I'm sorry to keep you waiting.
　---Oh, not at all. I ___ here only a few minutes.
A. have been　 B. had been　 C. was　D. will be
　 答案A. 等待的动作由过去开始，持续到现在，应用现在完成时。

11.15 过去完成时
1） 概念：表示过去的过去
-------------------->其构成是had +过去分词构成。
那时以前　 那时　现在　　　　　　

2） 用法
　a.　在told, said, knew, heard, thought等动词后的宾语从句。
　　 She said (that) she had never been to Paris.
　b. 状语从句
　　 在过去不同时间发生的两个动作中，发生在先，用过去完成时；发生在后，用一般过去时。
　　 When the police arrived, the thieves had run away.
　c. 表示意向的动词，如hope, wish, expect, think, intend, mean, suppose等，用过去完成时表示"原本…，未能…"
　　 We had hoped that you would come, but you didn't.

3)　过去完成时的时间状语before, by, until , when, after, once, as soon as。
　 He said that he had learned some English before.
　 By the time he was twelve, Edison had began to make a living by himself.
　Tom was disappointed that most of the guests had left when he arrived at the party.

典型例题　
　 The students ___ busily when Miss Brown went to get a book she ___ in the office.　
A. had written, left　B，were writing, has left　 C. had written, had left　D. were writing, had left
　 答案D. "把书忘在办公室"发生在"去取书"这一过去的动作之前，因此"忘了书"这一动作发生在过去的过去，用过去完成时。句中 when表示的是时间的一点，表示在"同学们正忙于……"这一背景下，when所引导的动作发生。因此
前一句应用过去进行时。

注意：　had no … when　　　　　还没等…… 就……
　　　　had no sooner… than　　刚…… 就……
　 He had no sooner bought the car than he sold it.

11.16 用一般过去时代替完成时
1)　两个动作如按顺序发生，又不强调先后，或用then，and，but 等连词时，多用一般过去时。
　　 When she saw the mouse， she screamed.
　　 My aunt gave me a hat and I lost it.

2 ) 两个动作相继发生，可用一般过去时；如第一个动作需要若干时间完成，用过去完成时。
　　 When I heard the news, I was very excited.

3)　叙述历史事实，可不用过去完成时，而只用一般过去时。
　　 Our teacher told us that Columbus discovered America in 1492.

11.17 将来完成时
　1) 构成will / be going to do sth.
　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，已经完成的动作或一获得的经验。
　　　They will have been married for 20 years by then.
　　　You will have reached Shanghai by this time tomorrow.
11.18 现在进行时
　现在进行时的基本用法：
　a. 表示现在( 指说话人说话时) 正在发生的事情。
　　 We are waiting for you.
　b. 习惯进行：表示长期的或重复性的动作，说话时动作未必正在进行。
　　 Mr. Green is writing another novel.　
　　　(说话时并未在写，只处于写作的状态。)
　　 She is learning piano under Mr. Smith.
　c. 表示渐变的动词有：get, grow, become, turn, run, go, begin等。
　　 The leaves are turning red.
　　 It's getting warmer and warmer.
　d. 与always, constantly, forever 等词连用，表示反复发生的动作或持续存在的状态，往往带有说话人的主观色彩。
　　 You are always changing your mind.

典型例题
　 My dictionary ___, I have looked for it everywhere but still___ it.　
　A. has lost, don't find　　 B. is missing, don't find　C. has lost, haven't found　 D. is missing, haven't found.　　
　 答案D. 前句是一个仍在持续的状态，应用进行时，由于没有找到，其影响仍然存在，应用完成时，瞬间动词用于否定式时可用于完成时。

11.19 不用进行时的动词
　1) 事实状态的动词
have, belong, possess, cost, owe, exist, include, contain, matter, weigh, measure, continue
　　I have two brothers.
　　This house belongs to my sister.

　2) 心理状态的动词
Know, realize, think see, believe, suppose, imagine, agree, recognize, remember, want, need, forget, prefer, mean, understand, love, hate
　　I need your help.
　　He loves her very much.

　3 ) 瞬间动词
accept, receive, complete, finish, give, allow, decide, refuse.
　　I accept your advice.

　4) 系动词
seem, remain, lie, see, hear, smell, feel, taste, get, become, turn
　　You seem a little tired.

11.20 过去进行时
1） 概念：表示过去某时正在进行的状态或动作。

2） 过去进行时的主要用法是描述一件事发生的背景；一个长动作发生的时候，另一个短动作发生。

3) 常用的时间状语
this morning, the whole morning, all day yesterday, from nine to ten last evening, when, while

　　 My brother fell while he was riding his bicycle and hurt himself.　
　　 It was raining when they left the station.
　　 When I got to the top of the mountain, the sun was shining.　

典型例题
1) Mary ___ a dress when she cut her finger.　
A. made　 B. is making　 C. was making　 D. makes
　 答案C. 割伤手指是已发生的事情，应用过去时。同　时，when表时间的同时性，"玛丽在做衣服时"提供事情发生的背景，因此用过去进行时。

2) As she ___ the newspaper, Granny ___ asleep.
read； was falling　B. was reading； fell　C. was reading； was falling　D. read； fell
　 答案B.句中的as = when, while，意为"当……之时"。描述一件事发生的背景时，用过去进行；一个长动作发生的时候，另一个短动作发生。句意为 "在她看报纸时，奶奶睡着了。"句中的 fell (fall的过去时)，是系动词，后跟形容词，如：fall sick。

11.21 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.
11.22 一般现在时代替将来时
时间状语从句，条件句中，从句用一般现在时代替将来时
When, while, before, after, till, once, as soon as, so long as, by the time, if, in case (that), unless, even if, whether, the moment, the minute, the day, the year, immediately

　 He is going to visit her aunt the day he arrives in Beijing. 他一到北京，就去看他姨妈。

典型例题
(1）He said he________me a present unless I_______ in doing the experiment.
　A. had not given; had not succeeded　　B. would not give; succeed
　C. will not give; succeed　　　　　　 D. would not give; will succeed.
　 答案B. 在时间，条件或让步主语从句中一般不用将来时。本题有He said，故为过去式。主句用将来时，故选B. 此处用一般过去式代替了过去将来时。

(2) 表示现在已安排好的未来事项，行程等活动。
　 The museum opens at ten tomorrow.　博物馆明天10点开门。(实际上每天如此。)

11.23 一般现在时代替过去时
1 )"书上说"，"报纸上说"等。
　 The newspaper says that it's going to be cold tomorrow.
　 报纸上说明天会很冷的。
2) 叙述往事，使其生动。
　 Napoleon's army now advances and the great battle begins.
11.24 一般现在时代替完成时
1) 有些动词用一般现在时代替完成时：
hear, tell, learn, write , understand, forget, know, find , say,　remember.
　 I hear (= have heard) he will go to London.
　I forget (=have forgotten) how old he is.
2) 句型 " It is … since…"代替"It has been … since …"
3) It is (= has been) five years since we last met.
11.25 一般现在时代替进行时
1) 句型：Here comes… ； There goes…
　 Look, here comes Mr. Li.

11.26 现在进行时代替将来时
1) 表示即将发生的或预定中计划好的活动。
　　Are you staying with us this weekend? 这周和我们一起度周末吗?
　　We are leaving soon.　 我们马上就走。
2) 渐变动词，如：get, run, grow, become, begin及die。
　　He is dying.
11.27 时态一致
　 1) 如果从句所叙述的为真理或不变的事实，则永远用现在时。
　At that time, people did not know that the earth moves.
　He told me last week that he is eighteen.

　 2) 宾语从句中的助动词ought, need, must, dare 时态是不变的。
　 He thought that I need not tell you the truth.

11.28 时态与时间状语
　　　　　　　　　时间状语
一般现在时　　every …, sometimes,　at …, on Sunday,

一般过去时　　yesterday, last week, an hour ago, the other day, in 1982, just now

一般将来时　　next…, tomorrow, in+时间,

现在完成时　　for, since, so far, ever, never, just, yet, till/until, up to now, in past years, always, recently

过去完成时　　 before, by, until, when, after, once, as soon as

过去进行时　　this morning, the whole morning, all day, yesterday, from nine to ten last evening… when, while

将来进行时　　soon, tomorrow, this evening, on Sunday, by this time, tomorrow, in two days, tomorrow evening