什么时候用Is 和 Do开头？怎么分辨哪个用Is哪个用Do？

Question

如题所述

Answer 1

1.原句有be动词，用is；没有就用do。
2.1）is是be动词.
be动词包括：am ,is ,are.
如果把一个句子变成疑问句,首先要看这个句子的动词是什么.
如果句中有be动词,直接把be动词提前.
例如：
This is a pen.有be动词,直接提前,就是Is this a pen?
They are eating apples.Are they eating apples?
2）do是助动词，句中没有be动词,而是实意动词,就得借助于助动词do 或 does 提问.
例如：
They had an oral english class yesterday.
had 是实意动词.借助助动词提问：Did they have an oral english class yesterday?
had 是过去式,所以用did 提问.变为疑问句的时候动词had 要还原为have.
He goes to school by bus everyday.go 是实意动词,就得借助助动词does提问.变为：Does he go to school by bus everyday?
he 是第三人称单数,所以用does 提问,疑问句中goes还原为go

Answer 2

当谓语动词是行为动词时，用do开头；当谓语动词是系动词is时，用is开头。
如果句子是一般疑问句，有be动词的直接把be动词提前，没有be动词的借助助动词do或does提问。