情態(tài)動(dòng)詞:

　　may/might表示允許和可能:

　　允許: 詢(xún)問(wèn)或說(shuō)明一件事可不可以做.

　　May I trouble you with a question?

　　You may take this seat if you like.

　　He asked if he might glance through my album.

　　You might as well speak your mind.

　　可能: 表示一件事或許發(fā)生.

　　You may walk ten miles without seeing a house.

　　She was afraid they might not like the idea.

　　A bad thing might be turned to good account.

　　might 表示請(qǐng)求:

　　Might I ask for a photograph of your baby?

　　cant, couldnt表示否定的推測(cè):

　　She cant be serious.

　　A more suitable book cant be found.

　　He couldnt be over fifty.

　　should, ought to: 表示應(yīng)該做的事, ought to比should口氣稍重一些.

　　You should do as he says.

　　You shouldnt talk like that.

　　但這兩者間也有一些差別, 在表示責(zé)任, 義務(wù)等該做的事情時(shí), 常用ought to, 在表示某件事宜于做時(shí), 多用should, 在下面的句子中這兩個(gè)詞就不宜換用:

　　You are his father. You ought to take care of him.

　　We should not use too many big words in our everyday speech.

　　will, would

　　shall, should表示意愿

　　情態(tài)動(dòng)詞后接進(jìn)行式, 完成式和完成進(jìn)行式:

　　情態(tài)動(dòng)詞可以和動(dòng)詞的進(jìn)行式構(gòu)成謂語(yǔ), 表示應(yīng)該正在, 想必正在這類(lèi)意思:

　　Why should we be sitting here doing nothing?

　　This isnt what I ought to be doing.

　　She might still be thinking about the question you raised.

　　They must be waiting for us, lets hurry up.

　　They cant be using the room now.

　　情態(tài)動(dòng)詞有時(shí)和動(dòng)詞的完成形式構(gòu)成謂語(yǔ), 表示應(yīng)當(dāng)已經(jīng), 想必已經(jīng)這類(lèi)意思:

　　I should have thought of that.

　　They shouldnt have left so soon.

　　She must have arrived by now.

　　You neednt have told them that.

　　Where can he have gone?

　　He cant have finished the work so soon.

　　He may not have achieved all his aims. But his effort is praise-worthy.

　　We ought to have give you more help.

　　情態(tài)動(dòng)詞間或也可以和一個(gè)動(dòng)詞的完成進(jìn)行式構(gòu)成謂語(yǔ),表示應(yīng)當(dāng)一直在, 想必一直在這類(lèi)意思:

　　They are sweating all over. They must have been working in the fields.

　　They may have been discussing the problem this morning.

　　You should have been waiting for us. Why havent you?

　　She couldnt have been swimming all day.

　　情態(tài)動(dòng)詞:

　　may/might表示允許和可能:

　　允許: 詢(xún)問(wèn)或說(shuō)明一件事可不可以做.

　　May I trouble you with a question?

　　You may take this seat if you like.

　　He asked if he might glance through my album.

　　You might as well speak your mind.

　　可能: 表示一件事或許發(fā)生.

　　You may walk ten miles without seeing a house.

　　She was afraid they might not like the idea.

　　A bad thing might be turned to good account.

　　might 表示請(qǐng)求:

　　Might I ask for a photograph of your baby?

　　cant, couldnt表示否定的推測(cè):

　　She cant be serious.

　　A more suitable book cant be found.

　　He couldnt be over fifty.

　　should, ought to: 表示應(yīng)該做的事, ought to比should口氣稍重一些.

　　You should do as he says.

　　You shouldnt talk like that.

　　但這兩者間也有一些差別, 在表示責(zé)任, 義務(wù)等該做的事情時(shí), 常用ought to, 在表示某件事宜于做時(shí), 多用should, 在下面的句子中這兩個(gè)詞就不宜換用:

　　You are his father. You ought to take care of him.

　　We should not use too many big words in our everyday speech.

　　will, would

　　shall, should表示意愿

　　情態(tài)動(dòng)詞后接進(jìn)行式, 完成式和完成進(jìn)行式:

　　情態(tài)動(dòng)詞可以和動(dòng)詞的進(jìn)行式構(gòu)成謂語(yǔ), 表示應(yīng)該正在, 想必正在這類(lèi)意思:

　　Why should we be sitting here doing nothing?

　　This isnt what I ought to be doing.

　　She might still be thinking about the question you raised.

　　They must be waiting for us, lets hurry up.

　　They cant be using the room now.

　　情態(tài)動(dòng)詞有時(shí)和動(dòng)詞的完成形式構(gòu)成謂語(yǔ), 表示應(yīng)當(dāng)已經(jīng), 想必已經(jīng)這類(lèi)意思:

　　I should have thought of that.

　　They shouldnt have left so soon.

　　She must have arrived by now.

　　You neednt have told them that.

　　Where can he have gone?

　　He cant have finished the work so soon.

　　He may not have achieved all his aims. But his effort is praise-worthy.

　　We ought to have give you more help.

　　情態(tài)動(dòng)詞間或也可以和一個(gè)動(dòng)詞的完成進(jìn)行式構(gòu)成謂語(yǔ),表示應(yīng)當(dāng)一直在, 想必一直在這類(lèi)意思:

　　They are sweating all over. They must have been working in the fields.

　　They may have been discussing the problem this morning.

　　You should have been waiting for us. Why havent you?

　　She couldnt have been swimming all day.