do和is的用法区别。

Question

如题所述

Answer 1

do的用法:1.做实义动词,有单三形式does,可以在句子中做谓语.
eg.i
often
do
my
homework.
he
often
does
his
homework.(做作业)
2.做助动词.同样有单三形式does,但是本身没有实在意义,只是用在否定句和一般疑问句中,与谓语动词一起构成否定和疑问结构.在变否定句和一般疑问句时,如果是实义动词(即不是be动词和情态动词)做谓语,则需要根据主语人称形式借助它们.
eg:
he
plays
football---he
doesn't
play
football
---does
he
play
football?
i
sing
a
song---i
don't
sing
a
song.
---do
you
sing
a
song?
需要注意:只要借了助动词,谓语动词的其他形式必须还原为原形.
is的用法:
is是属于be动词(即系动词),用于第三人称单数形式的主语后面,它的否定句直接在后面加not,一般疑问句直接把它提前.
eg.he
is
a
student---he
isn't
a
student
---is
he
a
student?
be动词用法口诀:我用am,你用are,is连着他她它,单数is复数are.