be動(dòng)詞，情態(tài)動(dòng)詞，助動(dòng)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(wèn)句時(shí)把a(bǔ)m，is，are提到句子的前面，句尾用問(wèn)號(hào)即可。變否定句時(shí)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(wèn)句: Is he a student?
否定句: He is not a student.
畫(huà)線提問(wèn):對(duì)he提問(wèn): Who is a student?
對(duì)a student提問(wèn): What is he? or What does he do?

2.由情態(tài)動(dòng)詞can, may, should等構(gòu)成的句子:變一般疑問(wèn)句時(shí)把can,may,提到句子的前面,句尾用問(wèn)號(hào)即可.變否定句時(shí)直接在can,may,后面加not即可.例如:
肯定句: She can swim.
一般疑問(wèn)句: Can she swim?
否定句: She can not swim.
畫(huà)線提問(wèn):對(duì)she提問(wèn): Who can swim?
對(duì)swim提問(wèn): What can she do?

3.由行為動(dòng)詞構(gòu)成的句子:需要加助詞do或does.變一般疑問(wèn)句時(shí)把do/does放在句子前面.變否定句時(shí)把don’t/doesn’t放在動(dòng)詞的前面。要注意觀察動(dòng)詞的形式并對(duì)號(hào)入座。一般疑問(wèn)句和否定句的動(dòng)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(wèn)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(huà)線提問(wèn):對(duì)they/he提問(wèn): Who plays football after school?  
對(duì)play football提問(wèn): What do they do after school?What does hedo after school?
對(duì)after school提問(wèn): When do they play football?When does heplay football?
 
針對(duì)性練習(xí)
按要求改寫(xiě)句子：
1.I know the answer.(一般疑問(wèn)句)         
  ______ ______ __________the answer?
2.We can see some birds.(一般疑問(wèn)句)
　______ ______ see ______ birds?
3.He designs clothes.(一般疑問(wèn)句)
   ______ he ________ clothes?
4.There are some flowers on the teachers’ desk.(一般疑問(wèn)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(wèn)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(wèn)句）
________ she _______ young?
13.She is young.（改為一般疑問(wèn)句）
______ ______ ____________?
14.My pencils are in the pencil-box.(對(duì)劃線部分提問(wèn))
______ ______ your pencils?
15.I get up at six every day.(對(duì)劃線部分提問(wèn))
______ ______ __________ you get up every day?
16.They like to walk home.(改為一般疑問(wèn)句)
______ they ________ _______ _______ _________?
17.These are cars.(用buses改寫(xiě)成選擇疑問(wèn)句)
　Are these cars______ ______ ?
18.My plant is one month old.(就劃線部分提問(wèn))
_______ ______ ______ _______ 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(wèn)）
　　_______ _______ ______ women __________?
23.He is happy, because he is going to take a trip tomorrow.（就劃線部分提問(wèn)）
_______ _______ ______ _________?
24.My father can cook the meals.（就劃線部分提問(wèn)）
_______ ________ ________ father __________?
25. You should add water often.（一般疑問(wèn)句）
_______ ______ _______ water often?
 
一、變否定句時(shí)相關(guān)詞的改變
　　肯定句變否定句時(shí)，除將謂語(yǔ)變?yōu)榉穸ㄊ酵?，句中其他詞語(yǔ)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(shù)上有些鳥(niǎo)。
　　→There aren’t any birds in the tree.樹(shù)上沒(méi)有鳥(niǎo)。
　　He likes the girl, too.他也喜歡這個(gè)女孩。
　　→He doesn’t like the girl, either.他也不喜歡這個(gè)女孩。
　　We have already seen the film.我們已看過(guò)這部電影。
　　→We have not seen the film yet.我們沒(méi)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(tīng)到這事時(shí)我們都笑了。(肯定句)
　　All of us didn’t laughed when we heard it.聽(tīng)到這事時(shí)我們并未都笑。(部分否定)
　　Not all of us laughed when we heard it.聽(tīng)到這事時(shí)我們并未都笑。(部分否定)
　　None of us laughed when we heard it.聽(tīng)到這事時(shí)我們都沒(méi)笑。(完全否定)
　　【注】可能涉及部分否定的詞語(yǔ)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(gè)…都”。