2、助动词have(has, had, having)的用法

(1)助动词have可以构成完成时或完成进行时

He has been a doctor for 10 years.他当医生十年了。

This is the place I have been longing to visit.这就是我一直渴望参观的地方。

(2)和不定式构成谓语，表示客观上不得不做的事情。

We've missed the train. We'll have to wait for another one.我们己经误了火车，我们只能等下一列。

-Do we have to start work?我们得立刻工作吗?

-No. We don't have to.不，不必了。

3、do(does, did) 的用法

(1)构成疑问句或否定句

How did you know about it?你是怎样知道这件事的。

He does not smoke. 他不抽烟。

(2)加强语气。

He did tell that.他的确告诉了此事。

Do come and see us.一定来看我们。

(3)代替前面刚出现的动词，避免重复。

-You like popular music, don't you?你喜欢流行音乐，是吧?

-Yes , I do.是的，我喜欢。

He speaks French as fluently as she does.他讲法语和她讲的一样流利。