動(dòng)詞do在句中的作用可以概述為四句十二字："做"實(shí)義，助動(dòng)詞，替前文，強(qiáng)語(yǔ)氣。

　　作用一：實(shí)義do

　　do作實(shí)義動(dòng)詞時(shí)，有do, does, did, done, doing五種形式，還有及物、不及物之分。如：

　　1. vt. "做；研究；整理；完成"。如：

　�、賂he old man does an hour of sport every day.

　　②She did her homework at home last night.

　　③Mother was doing the cooking when I reached home.

　�、蹾ave you done the exercises yet?

　　2. vi. "行動(dòng)；工作；進(jìn)展；足夠"。如：

　�、貹ate does very well in her Chinese.

　�、贖ow do you do?

　�、踂ell done!

　　④That will do.

　　作用二：助動(dòng)do

　　do作助動(dòng)詞時(shí)，只有do, does, did三種形式，無(wú)詞義，限用于含行為動(dòng)詞的一般現(xiàn)在時(shí)和一般過(guò)去時(shí)兩種時(shí)態(tài)的否定句和疑問(wèn)句中。如：

　�、賂hey don't have any tickets for tonight's concert.

　　②Kate stayed at home last night, didn't she?

　�、跦ow many books does the library have?