一． 动词的时态 时态是谓语动词所表示的动作或情况发生时间的各种形式。
(一） 一般现在时（do / does） 1．具体用法1) 表示经常性或习惯性动作We always care for each other and help each other. 我们总是互相关心互相帮助。He goes to school every day.2) 表示现在的特征或状态He is very happy.Do you sing? ----A little.3) 表示普遍真理Light travels faster than sound. 光速比声速快。Actions speak louder than words. 行动胜过言语。
* 常与一般现在时态连用的词或短语主要有：often, usually, sometimes, every day,
every morning/afternoon, on Sundays/weekends等等。
I often go to the cinema on Sundays. 我经常星期天去看电影。
He goes to work early every day. 他每天上班很早。
（二）一般过去时( did )
（1）表示过去某一特定时间所发生的、可完成的动作或状态，常与表示确切过去时间的词、短语或从句连用。例如：We went to the pictures last night and saw a very interesting film.
（2）表示过去习惯性动作。例如：He always went to class last. I used to do my homework in the library.
（三）一般将来时 ( will / shall do)
1）表示将来打算进行或期待发生的动作或状态。例如：I shall graduate next year.
2）一般将来时有时可以表示一种倾向或习惯性动作。如Crops will die without water.
You won’t succeed without their support.
3) 几种替代形式：
*be going to +v在口语中广泛使用，表示准备做或将发生的事情。例如：
I'm going to buy a house when we've saved enough money.
*be to +v表示计划安排要做的事，具有"必要"的强制性意义。例：I am to play tennis this afternoon.
*be about to +v表示即将发生的事情。例如：He was about to start.
*be due to +v表示预先确定了的事， 必定发生的事。例如：The train is due to depart in ten minutes.
5）少数动词如：begin, come, leave, go, arrive, start, stop, return, open, close等的一般现在时可用来表示将来的动作。（多用来表示按计划事先安排好即将发生的动作，句中通常还有一个表示将来的时间状语）。例如：The meeting begins at seven.The train starts at nine in the morning.
（四）现在进行时 ( is / are doing)
1） 表示现在某时或某段时间内正在进行的动作。常与现在进行时连用的词组
是now， right now，at the mother，for the time being，for the present, 或某个具体的时间（几点钟）。Eg:He is writing a letter now.She is visiting Beijing this week.
2） 有时用来代替一般现在时态，表示一个经常性动作或状态，这时是为了表示
一种感情（如赞叹，厌烦，满意，不满等）Eg:He is always thinking of his work. (表示赞许)
The boy is alway
s talking in class. （表示不满）
3) 有时用来表示一个在最近按计划或安排要进行的动作（这时多有一个表示未来的时间的状语）Eg:We are leaving on Friday. 我们星期五动身。How many of you are coming to the party?
（五）现在完成时（have / has done）
（1）现在完成时用来表示对目前状况仍有影响的，刚刚完成的动作（常与yet，already，just连用），或者过去某一时刻发生的，持续到现在的情况（常与for，since连用）。例如：
I have just finished my homework.Mary has been ill for three days.
（2）常与现在完成时连用的时间状语有：since, for, during, over等引导出的短语；副词already, yet, just, ever, now, before, often, lately, recently等；状语词组this week (morning, month, year), so far, up to now, many times, up to the present等。例如：So far, she hasn't enjoyed the summer vacation.There have been a lot of changes since 1978.
（3）完成时态可用在下列结构中：
*This (That, It) is (was) the first (second...) time +定语从句；
*This (That, It) is (was) the only (last) + n +定语从句；
*This (That, It) is (was) +形容词最高级+ n +定语从句。
如果主句的谓语动词是一般现在时，从句的谓语动词通常用现在完成时；如果主句谓语动词是一般过去时，从句谓语动词通常用过去完成时。例如：（1）This is one of the rarest questions that have ever been raised at such a meeting.（2）There was a knock at the door. It was the second time someone had interrupted me that evening.
（六）过去进行时 (was / were doing)
过去进行时表一个过去的动作发生时或发生后，另一个过去的动作正在进行，或表示过去反复的习惯，常与always，continually，constantly等动词连用.例如：1）We were discussing the matter when the headmaster entered.2）Whenever I visited him, he was always writing at the desk.
（七）过去完成时 ( had done)
（1）表示过去某时间前已经发生的动作或情况，这个过去的时间可以用by，before等介词短语或一个时间状语从句来表示；或者表示一个动作在另一个过去动作之前已经完成。Eg:
1）We had just had our breakfast when Tom came in.
2）By the end of last year they had turned out 5, 000 bicycles.
（2）动词expect, hope, mean, intend, plan, suppose, wish, want, desire等用过去完成时，表示过去的希望、预期、意图或愿望等没有实现。例如：I had meant to take a good holiday this year, but I wasn't able to get away.另外两种表示"过去想做而未做的事"的表达方式是：
1）was / were + to have done sth, 例如:We were to have come yesterday, but we couldn't.
2）intended (expected, hope, meant, planned, supposed, wished, wanted, desired) + to have done sth, 如：I meant to have told you about it, but I forgot to do so.
（3）过去完成时常用
于以下固定句型：
1）hardly, scarcely, barely + 过去完成时+ when + 过去时。例如：Hardly had I got on the bus when it started to move.2）no sooner +过去完成时+ than +过去时。例如: No sooner had I gone out than he came to see me.3）by (the end of ) +过去时间，主句中谓语动词用过去完成时。例如：The experiment had been finished by 4 o'clock yesterday afternoon.
(八)一般过去将来时
1. 一般过去将来时的形式 :Should / would+ 动词原形 & was / were + 动词-ing形式
2. 一般过去将来时常用于宾语从句中，其主语的谓语动词为过去时态，可表示从过去某时看来将要发生的事情，如：He said that he would speak at the meeting.
He was sixty-eight. In two years he would be seventy.
（九）现在完成进行时 ( has / have been doing)
现在完成进行时表示过去某一时刻之前开始的动作或状态一直延续到过去某一时刻。例如：
I have been looking for my lost book for three days, but I still haven't found it.