定義： 動詞以一定的詞形變化形式來表達(dá)事物之動作或狀態(tài)的時(shí)間性者稱為時(shí)態(tài)(Tense)。

詞形變化的形式共有如下四種：

1.一般式(Simple Form)

2.進(jìn)行式(Progressive Form)

3.完成式(Perfect Form)

4.完成進(jìn)行式(Perfect Progressive Form)

動作或狀態(tài)的時(shí)間性則可分為如下三個(gè)時(shí)段：

1.現(xiàn)在(Present)

2.過去(Past)

3.將來(Future)

這四種詞形形式和三個(gè)時(shí)段可以配合成如下的十二種動詞的時(shí)態(tài)。

這十二種時(shí)態(tài)可以列表如下：

現(xiàn)以“I”為主語，“do”為動詞，把這十二種時(shí)態(tài)以實(shí)例表達(dá)如下：(例序即為時(shí)態(tài)的次序)

1.I do it every day.

(我每天做這樣的事。)

2.I did it yesterday.

(昨天我做了這件事。)

3.I shall/will do it tomorrow.

(明天我要做這件事。)

4.I am doing it now.

(現(xiàn)在我正在做這件事。)

5.I was doing it at that time.

(當(dāng)時(shí)我正在做這件事。)

6.I shall/will be doing it at 9：00 tomorrow morning.

(明天早晨九時(shí)我會正在做這件事。)

7.I have done it already.

(我已把這件事做好了。)

8.I have done it before I went home yesterday.

(昨天我在回家之前就把那件工作做完了。)

9.I shall/will have done it before you come back tomorrow.

(明天在我回來之前我會把這件工作做好。)

10.I have been doing it for two days.

(這件工作我已做了兩天了。──說話時(shí)工作尚未做完，所以還得繼續(xù)做。)

11.I had been doing the work for two hours when the teacher came.

(老師來時(shí)那件工作我已做了兩小時(shí)了。──當(dāng)時(shí)工作尚未完成，所以老師來了我還繼續(xù)在做。)

12.I shall/will have been doing it for an hour when you come to see me at 9：00 tomorrow morning.

(明天早上九時(shí)你來看我時(shí)，我會在做那件工作做了一小時(shí)。──當(dāng)然尚未能做完，還得繼續(xù)做下去。)