4、　 情态动词后还可接不定式的进行式、完成式和被动式。

例如：He can’t be doing his homework now. 他现在不可能在做功课。

He must have attended the meeting last night. 昨晚他一定参加了会议。

(二)虚拟语气

3、　 情态动词的过去式，例如can-could，may-might。但是少数情态动词只有过去式，例如used to表示过去常常。must的过去式往往用had to代替。

2、含有情态动词的句子改为否定句或疑问句不必加助动词，只需要将情态动词置于主语前，或在情态动词后加上not。

例如：Must I write a letter to cheer him up?

You needn’t wait for me.

(一)情态动词

1、情态动词在句中没有人称和数的变化。

7．　 在It is time that, I would rather that句式中从句谓语动词用过去式。例如：

It is time we went to bed.

I would rather he came next week.

第二节 实战演练

6．　 在有些句型中如：It is important (necessary、natural、strange等) + that从句中的谓语动词用should + 动词原形，should可以省略。例如：

It is necessary that the doctor (should) be sent there at once.

5．　 在有些动词如：suggest、insist、order等动词后，从句谓语动词用“should + 动词原形”，should可以省略。例如：

He suggested that we (should) discuss the problem right now.

4．　 动词wish后的宾语从句中，谓语动词可用过去式、过去完成式或would、might加原形。

例如：I wish I were as strong as you.

He wished I would stay with us.

She wished I had attended the meeting yesterday.

3．　 表示与将来事实相反的谓语形式。

例如：If they came tomorrow, we would told them about it. (In fact, they won’t come tomorrow。)

2．　 表示与过去事实相反的谓语形式。

例如：If I had left a little earlier, I would have caught the early bus. (In fact, I didn’t catch the bus.)