定義 動詞以一定的詞形變化形式來表達事物之動作或狀態的時間性者稱為時態(Tense)。

詞形變化的形式共有如下四種：

1.一般式(Simple Form)

2.進行式(Progressive Form)

3.完成式(Perfect Form)

4.完成進行式(Perfect Progressive Form)

動作或狀態的時間性則可分為如下三個時段：

1.現在(Present)

2.過去(Past)

3.將來(Future)

這四種詞形形式和三個時段可以配合成如下的十二種動詞的時態。

這十二種時態可以列表如下：

現以“I”為主語，“do”為動詞，把這十二種時態以實例表達如下：(例序即為時態的次序)

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.

(現在我正在做這件事。)

5.I was doing it at that time.

(當時我正在做這件事。)

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。──說話時工作尚未做完，所以還得繼續做。)

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

(老師來時那件工作我已做了兩小時了。──當時工作尚未完成，所以老師來了我還繼續在做。)

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