2018年公共英语一级语法讲解：动词的时态
(一)、 一般现在时
1.概念：经常、反复发生的动作或行为及现在的某种状况。
2.时间状语： Always, usually, often, sometimes, every week (day, year, month…), once a week(day, year, month…), on Sundays,
3.基本结构：动词 原形 (如主语为第三人称单数，动词上要改为第三人称单数形式)
4.否定形式：主语+am/is/are +not+其他; 此时态的谓语动词若为行为动词，则在其前加don't, 如主语为第三人称单数，则用doesn't，同时还原行为动词。
5.一般疑问句：把be动词放于句首;用助动词do提问，如主语为第三人称单数，则用does，同时，还原行为动词。
6.例句：It seldom snows here.
He is always ready to help others.
Action speaks louder than words..
(二)、 一般过去时
1.概念：过去某个时间里发生的动作或状态;过去习惯性、经常性的动作、行为。
2.时间状语：ago, yesterday, the day before yesterday, last week, last(year, night, month…), in 1989, just now, at the age of 5, one day, long long ago, once upon a time, etc.
3.基本结构：be动词;行为动词 的过去式
4.否定形式：主语+was/were +not+其他;在行为动词前加didn't，同时还原行为动词。
5.一般疑问句：was或were放于句首;用助动词do的过去式did 提问，同时还原行为动词。
6.例句：She often came to help us in those days.
I didn't know you were so busy.
(三)、 现在进行时
1.概念：表示现阶段或说话时正在进行的动作及行为。
2.时间状语：Now, at this time, days, etc. look. listen
3.基本结构：主语+be +doing +其他
4.否定形式：主语+be +not +doing+其他
5.一般疑问句：把be动词放于句首。
6.例句： How are you feeling today?
He is doing well in his lessons.
7. 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。
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.
(四)、 过去进行时
1.概念：表示过去某段时间或某一时刻正在发生或进行的行为或动作。
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。时间状语：at this time yesterday, at that time或以when引导的谓语动词是一般过去时的时间状语等。
3.基本结构 主语+was/were +doing +其他
4.否定形式：主语+was/were + not +doing+其他
5.一般疑问句：把was或were放于句首。(第一个字母大写)
6.例句：At that time she was working in a PLA unit.
When he came in, I was reading a newspaper.
典型例题
1) Mary ___ a dress when she cut her finger.
A. madeB. is makingC. was makingD. 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 fallingB. was reading; fellC. was reading; was fallingD. 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。
(五)、 现在完成时
1.概念：过去发生或已经完成的动作对现在造成的影响或结果，或从过去已经开始，持续到现在的动作或状态。
2.时间状语：yet,already,just,never,ever,so far,by now,since+时间点，for+时间段，recently, lately, in the past few years, etc.
3.基本结构：主语+have/has +p.p(过去分词)+其他
4.否定形式：主语+have/has + not +p.p(过去分词)+其他
5.一般疑问句：have或has。
6.例句：I've written an article.
The countryside has changed a lot in the past few years.
(六)、注意： 用过去时表示现在，表示委婉语气。
1)动词want, hope, wonder, think, intend 等。
Did you want anything else?
I wondered if you could help me.
2)情态动词 could, would.
Could you lend me your bike?
used to/be used to
used to + do："过去常常"表示过去习惯性的动作或状态，但如今已不存在。
Mother used not to be so forgetful.
Scarf used to take a walk.(过去常常散步)
be used to + doing： 对……已感到习惯，或"习惯于"，to是介词，后需加名词或动名词。
He is used to a vegetarian diet.
Scarf is used to taking a walk.(现在习惯于散步)
典型例题
---- Your phone number again? I ___ quite catch it.
---- It's 69568442.
A. didn'tB. couldn'tC. don'tD. can't
答案A. 本句虽没有明确的时间状语，但从语意上看 出，在听的时候没有听懂这个动作发生在过去，因此应用过去时。
(七)、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.
4)be about to +不定式，意为马上做某事。
He is about to leave for Beijing.
注意：be about to 不能与tomorrow, next week 等表示明确将来时的时间状语连用。
be going to/will
用于条件句时， be going to表将来
will表意愿
If you are going to make a journey, you'd better get ready for it as soon as possible.
Now if you will take off your clothes, we will fit the new clothes on you in front of the mirror.
be to和be going to
be to 表示客观安排或受人指示而做某事。
be going to 表示主观的打算或计划。
I am to play football tomorrow afternoon. (客观安排)
I'm going to play football tomorrow afternoon. (主观安排)
一般现在时表将来
1)下列动词：come, go, arrive, leave, start, begin, return的一般现在时表将来。这主要用来表示在时间上已确定或安排好的事情。
The train leaves at six tomorrow morning.
When does the bus star? It stars in ten minutes.
2)倒装句，表示动作正在进行，如：
Here comes the bus. = The bus is coming.
There goes the bell. = The bell is ringing.
3)在时间或条件句中。
When Bill comes (不是will come), ask him to wait for me.
I'll write to you as soon as I arrive there.
4)在动词hope, take care that, make sure that等后。
I hope they have a nice time next week.
Make sure that the windows are closed before you leave the room.
用现在进行时表示将来
意为："意图"、"打算"、"安排"、常用于人。常用词为 come, go, start, arrive, leave, stay等。
I'm leaving tomorrow.
Are you staying here till next week?
现在完成时
现在完成时用来表示之前已发生或完成的动作或状态，其结果的确和现在有联系。动作或状态发生在过去但它的影响现在还存在;也可表示持续到现在的动作或状态。其构成： have (has) +过去分词。
用于现在完成时的句型
1)It is the first / second time…. that…结构中的从句部分，用现在完成时。
It is the first time that I have visited the city.
It was the third time that the boy had been late.
2)This is the… that…结构，that 从句要用现在完成时.
This is the best film that I've (ever) seen.
这是我看过的最好的电影。
This is the first time (that) I've heard him sing.这是我第一次听他唱歌。
典型例题
(1) ---Do you know our town at all?
---No, this is the first time I ___ here.
A. wasB. have beenC. cameD. am coming
答案B. This is the first time 后面所加从句应为现在完成时，故选B。
(2) ---Have you ____ been to our town before?
---No, it's the first time I ___ here.
A. even, comeB. even, have comeC. ever, comeD. ever, have come
答案D. ever意为曾经或无论何时，反意词为never，此两词常用于完成时。 This is the largest fish I have ever seen. It is / was the first time +that-clause 的句型中，从句要用完成时。
注意：非延续性动词的否定形式可以与表示延续时间的状语连用。即动作不发生的状态是可以持续的。
(错)I have received his letter for a month.
(对)I haven't received his letter for almost a month.
比较since和for
Since 用来说明动作起始时间，for用来说明动作延续时间长度。
I have lived here for more than twenty years.
I have lived here since I was born..
My aunt has worked in a clinic since 1949.
Some new oilfields have been opened up since 1976.
I have known Xiao Li since she was a little girl.
My brother has been in the Youth League for two years.
I have not heard from my uncle for a long time.
注意：并非有for 作为时间状语的句子都用现在完成时。
I worked here for more than twenty years. (我现在已不在这里工作。)
I have worked here for many years. (现在我仍在这里工作。)
小窍门：当现在完成时+一段时间，这一结构中，我们用下面的公式转化，很容易就能排除非延续动词在完成时中的误使。
1)(对) Tom has studied Russian for three years.
= Tom began to study Russian three years ago, and is still studying it now.
2)(错) Harry has got married for six years.
= Harry began to get married six years ago, and is still getting married now.
显然，第二句不对，它应改为 Harry got married six years ago.或 Harry has been married for six years.
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.
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 metB. have metC. metD. 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。
(八)、 一般过去时与现在完成时的转换
在现在完成时中，延续性动词能与表示一段时间的状语连用，瞬间动词却不能。但是，可用别的表达方式：①瞬间动词用于“一段时间 + ago”的一般过去时的句型中;②瞬间动词可改成与之相对应的延续性动词及短语，与一段时间连用;③瞬间动词用于“It is + 一段时间 + since + 一般过去时”的句型中，表示“自从……以来有……时间”的意思，主句一般用it is来代替It has been;④瞬间动词用于“Some time has passed since + 一般过去时”的句型中。请看：
A. He joined the League two years ago.
B. He has been in the League for two years.
C. It is two years since he joined the League.
D. Two years has passed since he joined the League.
(九)、一般现在时与现在进行时的转换
在一般现在时中，at加上名词表示“处于某种状态”，如at work(在工作), at school(上学、上课)等。此短语可与进行时态转换。请看：
Peter is at work, but Mike is at play.
Peter is working, but Mike is playing.
(十)、 现在进行时与一般将来时的转换
在现在进行时态中go, come, leave, start, arrive等动词常与表示将来的时间状语连用表示将要发生的动作。如：I am coming, Mum! 意为“我就来，妈妈!”请看：
The train is leaving soon. The train will leave soon.
