五种半情态动词短语had better（would rather have to等的真面目）

记录典型问题 分享教学方法

S: 学生 T: 老师

S: 老师，would rather是情态动词吗？它后面为什么既可以跟动词原形，又可以跟从句？比如：

I would rather stay at home.

I would rather you came tomorrow.

T:关于短语would rather的词性，可以这样理解：

后面跟动词原形时，是情态动词；

后面跟宾语从句时，是行为动词。

故可称之为：半情态动词短语。

S: 这样的半情态动词短语还有哪些？

T:总结一下：五大半情态动词短语

would rather, had better, have to, used to, ought to.

三大共同点：

1. 意义上都带有某种“情感态度”，如：

would /had rather 宁愿，宁可

had better/best 最好

have to 不得不，必须

used to 过去常常

ought to 应该，理应

2. 其后都跟动词原形；

3. 疑问与否定都可由自身来完成，

（have to 例外）即：

1) would rather not do, 疑问将would提到句首；

2) had better not do, 疑问had提句首；

3）ought not to do, 疑问将ought提句首；

4）used not to do或didn’t used to do, 疑问将used提句首或借助did完成；

5）have to 有点例外，其否定和疑问借助do来完成；且有第三人称单数形式has to, 过去式had to。

S: 此三大共同点符合情态动词的基本特征。

T: 值得注意的用法：

1. 虚拟用法

1)ought to + have done 过去本应做，而事实上未做（=should have done);

如：You ought to have visited him.

2)would rather + have done 表主语（本人）想要做某事，可结果事与愿违；

如：I’d rather have left a message to her.

3)would rather + 从句（从句时态为did或had done) 表主语想要某人做某事，可结果事与愿违。

如：I’d rather they arrived on Sunday.

I’d rather he hadn’t told me the news.

2. 习语“宁愿......而不愿.......”

would rather do sth than do sth

=would do sth rather than do sth;

=prefer to do sth rather than do sth.

此结构中，若前后动词相同，则than后动词可省，此时注意than前后的平行结构。如：

I’d rather go on Sunday than（go）on Monday.

He’d rather travel by train than by car.

3.关于have to ， 表示客观必要性，译为“不得不”，否定译为“不必”。

1）其否定和疑问借助do构成，如：

You don"t have to start so early.

Does he have to go with you ？

2）可用于多种时态及被动语态，如：

It will have to be done all over again.

A lot of work had to be done.

3）可与may，might 连用，如：

We may/might have to go now.

4）= have got to ，但have got to的疑问及否定由have完成，如：

Has he got to go home now？

You haven"t got to lend her money.

本节课教与学方法提炼：词以类记法

物以类聚，人以群分;

词以类记，词以类学。