be动词,情态动词,助动词do

be动词，情态动词，助动词do/does的用法区别及练习

1.由连系am，is，are构成的句子：变一般疑问句时把am，is，are提到句子的前面，句尾用问号即可。变否定句时直接在am，is，are后面加not即可。例如：

肯定句:He is a student.

一般疑问句: Is he a student?

否定句: He is not a student.

画线提问:对he提问: Who is a student?

对a student提问: What is he? or What does he do?

2.由情态动词can, may, should等构成的句子:变一般疑问句时把can,may,提到句子的前面,句尾用问号即可.变否定句时直接在can,may,后面加not即可.例如:

肯定句: She can swim.

一般疑问句: Can she swim?

否定句: She can not swim.

画线提问:对she提问: Who can swim?

对swim提问: What can she do?

3.由行为动词构成的句子:需要加助词do或does.变一般疑问句时把do/does放在句子前面.变否定句时把don’t/doesn’t放在动词的前面。要注意观察动词的形式并对号入座。一般疑问句和否定句的动词三单式都要变回原型。

play-----do plays-----does

例如:

肯定句: They play football after school. He plays football after school.

一般疑问句: Do they play football after school? Does he play football after school?

否定句: They don't (do not) play football after school.He doesn’t’play football after school.

画线提问:对they/he提问: Who plays football after school?

对play football提问: What do they do after school?What does he do after school?对after school提问: When do they play football?When does he play football?

针对性练习

按要求改写句子：

1.I know the answer.(一般疑问句)

______ ______ __________the answer?

2.We can see some birds.(一般疑问句)

______ ______ see ______ birds?

3.He designs clothes.(一般疑问句)

______ he ________ clothes?

4.There are some flowers on the teachers’ desk.(一般疑问句)

______ ______ ______ flowers on the teachers’ desk?

5.There are some apples on the tree.(否定句)

There ______ ______ ______ apples on the tree.

6.I think he is very old.(否定句)

I ______ think he ______ very old.

7.Please colour it green.(否定句)

______ ______ colour it green.

8.These doctors are helpful.(变否定句)

______ _______ ______ __________.

9.You may have some hot dogs.(一般疑问句)

_______ ______ ______ ______ ________?.

10.There aren’t a ny pears in the box.(同义句)

There are ______ pears in the box.

11.This sign means “No smoking”.

What ______ this sign _________?

12.She looks young.（改一般疑问句）

________ she _______ young?

13.She is young.（改为一般疑问句）

______ ______ ____________?

14.My pencils are in the pencil-box.(对划线部分提问)

______ ______ your pencils?

15.I get up at six every day.(对划线部分提问)

______ ______ __________ you get up every day?

16.They like to walk home.(改为一般疑问句)

______ they ________ _______ _______ _________?

17.These are cars.(用buses改写成选择疑问句)

Are these cars______ ______ ?

18.My plant is one month old.(就划线部分提问)

_______ ______ ______ _______ plant?

19.Two boys are in our house.(改为there be句型)

______ ______ two boys in our house.

20.My plant has two green leaves.

_______ ______ _______ ______ ______ _______plant __________? 21.Miss Li goes to Hong Kong by plane.（同义句）

Miss Li ________ _________ Hong Kong.

22. The women work in the shoe factory.（就划线部分提问）

_______ _______ ______ women __________?

23.He is happy, because he is going to take a trip tomorrow.（就划线部分提问）_______ _______ ______ _________?

24.My father can cook the meals.（就划线部分提问）

_______ ________ ________ father __________?

25. You should add water often.（一般疑问句）

_______ ______ _______ water often?

一、变否定句时相关词的改变

肯定句变否定句时，除将谓语变为否定式外，句中其他词语也可能随之改变，如将some