be動詞，情態(tài)動詞，助動詞do/does的用法區(qū)別及練習(xí)
1.    由連系am，is，are構(gòu)成的句子：變一般疑問句時把a(bǔ)m，is，are提到句子的前面，句尾用問號即可。變否定句時直接在am，is，are后面加not即可。例如：
肯定句:He is a student.
一般疑問句: Is he a student?
否定句: He is not a student.
畫線提問:對he提問: Who is a student?
對a student提問: What is he? or What does he do?

2.由情態(tài)動詞can, may, should等構(gòu)成的句子:變一般疑問句時把can,may,提到句子的前面,句尾用問號即可.變否定句時直接在can,may,后面加not即可.例如:
肯定句: She can swim.
一般疑問句: Can she swim?
否定句: She can not swim.
畫線提問:對she提問: Who can swim?
對swim提問: What can she do?

3.由行為動詞構(gòu)成的句子:需要加助詞do或does.變一般疑問句時把do/does放在句子前面.變否定句時把don’t/doesn’t放在動詞的前面。要注意觀察動詞的形式并對號入座。一般疑問句和否定句的動詞三單式都要變回原型。
play-----do     plays-----does
 
例如:
肯定句: They play football after school.    He plays football after school.
一般疑問句: Do they play football after school?   Does heplay football after school?
否定句: They don't (do not) play football after school.He doesn’t’play football after school.
畫線提問:對they/he提問: Who plays football after school?  
對play football提問: What do they do after school?What does hedo after school?
對after school提問: When do they play football?When does heplay football?
 
針對性練習(xí)
按要求改寫句子：
1.I know the answer.(一般疑問句)         
  ______ ______ __________the answer?
2.We can see some birds.(一般疑問句)
　______ ______ see ______ birds?
3.He designs clothes.(一般疑問句)
   ______ he ________ clothes?
4.There are some flowers on the teachers’ desk.(一般疑問句)
______ ______ ______ 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.(變否定句)
______ _______ ______ __________.
9.You may have some hot dogs.(一般疑問句)
_______ ______ ______ ______ ________?.
10.There aren’t any pears in the box.(同義句)
There are ______ pears in the box.
11.This sign means “No smoking”.
　What ______ this sign _________?
12.She looks young.（改一般疑問句）
________ she _______ young?
13.She is young.（改為一般疑問句）
______ ______ ____________?
14.My pencils are in the pencil-box.(對劃線部分提問)
______ ______ your pencils?
15.I get up at six every day.(對劃線部分提問)
______ ______ __________ you get up every day?
16.They like to walk home.(改為一般疑問句)
______ they ________ _______ _______ _________?
17.These are cars.(用buses改寫成選擇疑問句)
　Are these cars______ ______ ?
18.My plant is one month old.(就劃線部分提問)
_______ ______ ______ _______ plant?
19.Two boys are in our house.(改為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.（同義句）
Miss Li ________ _________ Hong Kong.
22. The women work in the shoe factory.（就劃線部分提問）
　　_______ _______ ______ women __________?
23.He is happy, because he is going to take a trip tomorrow.（就劃線部分提問）
_______ _______ ______ _________?
24.My father can cook the meals.（就劃線部分提問）
_______ ________ ________ father __________?
25. You should add water often.（一般疑問句）
_______ ______ _______ water often?
 
一、變否定句時相關(guān)詞的改變
　　肯定句變否定句時，除將謂語變?yōu)榉穸ㄊ酵?，句中其他詞語也可能隨之改變，如將some改為any，too和also改為either，already改為yet，and改為or等：
　　There are some birds in the tree.樹上有些鳥。
　　→There aren’t any birds in the tree.樹上沒有鳥。
　　He likes the girl, too.他也喜歡這個女孩。
　　→He doesn’t like the girl, either.他也不喜歡這個女孩。
　　We have already seen the film.我們已看過這部電影。
　　→We have not seen the film yet.我們沒有看這部電影。
　　He likes singing and dancing.他喜歡唱歌和跳舞。
　　→He doesn’t like singing or dancing.他不喜歡唱歌也不喜歡跳舞。
　二、部分否定與完全否定
　　比較以下句子：
　　All of us laughed when we heard it.聽到這事時我們都笑了。(肯定句)
　　All of us didn’t laughed when we heard it.聽到這事時我們并未都笑。(部分否定)
　　Not all of us laughed when we heard it.聽到這事時我們并未都笑。(部分否定)
　　None of us laughed when we heard it.聽到這事時我們都沒笑。(完全否定)
　　【注】可能涉及部分否定的詞語有both, all, always, every等，即not both表示“并非兩者都”，not all表示“并非所有的都”，not always表示“并非總是”，not every表示“并非每個…都”。