is是be动词,是描述性的,she is beautiful.is左右两边有等号概念.Is she beautiful? does助动词,表示行为、具体的动作,does是人称的不同造成的,第一、二人称用do,第三人称单数用does.如she likes icecream.like就是一个表示行为的动词,因而变成一般疑问句时,要加助动词does.Does she like icecream?
do 或者does叫做助动词,是帮助主动词构成疑问,否定等。但是只有谓语动词(主动词)是“行为动词”(与“状态动词”比如is等相对)的时候才用。 He likes music. Does he like music? He doesn't like music. 这里都不能用is。 He is a student. Is he a student?