be动词和实意动词俩个不能同时用是吧?那为啥说I am writing to you to .这里的am 和 writi
4个回答

动词根据构成谓语方式可分成两种:1构成合成谓语的特殊动词.共有12个.2.可以单独构成谓语的普通实义动词.

be动词有双重属性,当be是特殊助动词时,可以和doing/done/to do/going to do/used to doing/构成合成谓语.

He is leaving.

The work is finished.

The president is to visit your country next week.

I am going to have a trip in a few days.

当be本身是实义动词时解释为是,在等含义时,就不能再和其他实义动词连用了.通常要把那个动词变成to do或doing来做表语了.

To see is to believe.

Seeing is believing.