知識重點與難點總結(jié)
知識重點：
情態(tài)動詞在表達推測意義的句子中的運用：
（一）用情態(tài)動詞表達事實的推測。can，could，might，may，must可以用來表達對事實的推測。根據(jù)說話人對事實的把握性大小，must表示“肯定…”，may / might / can / could表示“可能……”， must只用于肯定句中，may / might的否定式may not / might not表示 “可能不……”, 而can / could可以用于疑問句，表示“可能，可能……嗎?”，其否定式can’t / couldn’t 表示“不可能”。用情態(tài)動詞可以對現(xiàn)在或過去的事實進行推測。對不同的時間內(nèi)容推測有不同的結(jié)構(gòu)。
（二）對現(xiàn)在的事實進行推測：
主要結(jié)構(gòu)：…must / may / might +動詞原形
be+名詞/形容詞/介詞短語
be + doing
例句：
1. You must be Jeanne. I’m Mathilde Loisel. We used to know each other very well.
2. They must be in bed already at this time of the night.
3. The teacher must be joking.
4. Freda isn’t in class. She must be sick.
5. There must be something wrong.
6. She might be very clever, but she hasn’t got much common sense.
7. He may be arriving this evening.
8. He may be traveling around the world.
9. The keys can’t be in the room. I have just searched it very carefully.
10. Can the news be true ?
（三）對過去的事實進行推測：結(jié)構(gòu)：情態(tài)動詞+have done / been+名詞/形容詞/介詞短語
例句：
1. Mrs. Longmans must have been a pretty girl in her youth.
2. He couldn’t have seen Anna yesterday. She’s gone abroad.
3. I think I must have left my glasses in the library.
4. He might have overslept again.
5. Where can Tom have gone ?
情態(tài)動詞表達虛擬語氣：表達“本來…”，“不然早就…”。這是情態(tài)動詞的一種虛擬語氣用法。表示說話人所講的與所發(fā)生的事實相反。表達了說話人的埋怨，后悔的語氣。其結(jié)構(gòu)是在一些情態(tài)動詞后面加 have done 結(jié)構(gòu)。根據(jù)要表達的意思，有如下結(jié)構(gòu)：
should have done / ought to have done：本應該……
shouldn’t have done / oughtn’t to have done：本不該……
could have done：本來可以……
needn’t have done：本來沒必要……
would like to have done：本來很想……
would rather not have done: 本來不愿意……
could / might / have done: 不然早就……
例句：
1. You shouldn’t have laughed at his mistakes.
2. You could have told us earlier.
3. I ought to have bought that dictionary last week.
4. You ought not to have spent so much time in reading novels.
5. We need not have been in a tearing hurry to catch the train.
6. They would like to have seen that film last film.
7. If he had given me his number, I could have telephoned him.
8. They might have been frozen to death but for the rescue in time.
知識難點：
某些情態(tài)動詞的特殊用法：
need 和dare 的兩種形式的用法
need 和dare可以用做實義動詞，后面接不定式（to do）結(jié)構(gòu)，在疑問句和否定句中，加助動詞do/does/did/或don’t/doesn’t/didn’t。作為情態(tài)動詞使用時，主要用于疑問句和否定句中。情態(tài)動詞needn’t（沒有必要，不必）相當于don’t have to
例句：
1. It is cold, you need to wear some warm clothes.
2. Need I stay here with you for a while ? Thank you, you needn’t.
3. How dare you speak to parents like that ?
注意：
句型I dare say+從句。 意思是：我肯定…… = I’m sure或There is no doubt that+從句。
例句：
I dare say that my uncle will get the money if I die.
will和would
表示“意志”或“愿意”，would 則指過去愿意做……
例句：
1. He said that he would help us.
2. You may telephone if you will accept this job.
would可以表達“過去習慣做……”類似于“used to do”
例句：
1. When we were children, we would go swimming every summer in that river.
表示請求，固定的句型：Will/Would you please do…? / Would you like to do…?
例句：Will/Would you please give him a message when you see him ?
shall
1. 用于第一，三人稱，表示“請求”；“建議” 或“推薦”
例句：
1. Shall we start the meeting now?
2. Shall I watch TV now ?
3. Shall my son carry the case for you ?
2. 用于第二人稱，表示“命令，“要求”，“許諾”
例句：
1. You shall take whatever you like.
2. You shall not go to the party with me if you make so much noise again.
在表示推測的否定句或疑問句中，常用can /can’t /could / couldn’t表示，意思是：“可能…嗎?”；“…不可能…”。而不能使用mustn’t或must等詞。
【典型例題】
1. —Do you think he will do me a favor ?
—As far as I know, he is the last one to help others. He _____ be prepared to give you a hand, though.
A. might B. must C. can D. should
分析：本題考查情態(tài)動詞推測性用法。 根據(jù)he is the last one to help others.（他是最不可能幫助別人的人），既然如此，那么“幫助你”的可能性也就最小了。 答案為A
2. —Look, someone is coming. Guess who it ____ be ?
—I think it ___ be Tom.
—I don’t think it ___ be ____ .
A. can ; must ; can ; he B. may ; can ; must ; him
C. must ; can ; must ; his D. might ; must ; can ; himself
分析：根據(jù)備選答案。 can表示推測時用于疑問句或否定句中。本題首句就應該是Guess who can it be? 第二句應該是I think it must be Tom.（說話人十分肯定）。第三句表達了說話人對前一個人的否定。即：I don’t think it can be him/he.（不可能是他）。答案為A
3. —Do you know Ms. Wang likes walking after supper ?
—Sure. She ____ around the campus now.
A. must be walking B. must walk
C. may walk D. may be walking
分析：關鍵詞Sure告訴我們說話人的口氣十分肯定。根據(jù)句子語境：她此刻肯定正在校園散步呢。must be doing表示肯定正在做。答案為A
4. —I stayed at a hotel in New York.
—Oh, did you ? You _____ with Barbara.
A. could have stayed B. could stay C. would say D. must have stayed
分析：首句說：我在紐約住在一家賓館里。在此a hotel是泛指。所以D選項不合題意。第二句在說：你本來可以和Barbara.住在一起的。Could have done表示：本來可以。答案為A
5. Why didn’t you tell me there was no meeting today ? I _____ all the way here through the heavy snow.
A. needn’t have driven B. can’t have driven
C. mustn’t have driven D. shouldn’t have driven
分析：根據(jù)句意：你為什么不告訴我今天沒有會？我本來沒必要冒著大雪開車跑這么多路。Needn’t have done表示本來沒必要。答案為A
6. I was really anxious about you. You _____ home without a word.
A. mustn’t leave B. shouldn’t have left
C. couldn’t have left D. needn’t leave
分析：根據(jù)句意：我真的很擔心你，你真不應該一句話都不說就離開家?！半x開家”已經(jīng)發(fā)生了。Should have done正好表達了本句的意思。答案為B
7. A：Are you coming to Jeff’s party ?
B：I’m not sure. I _____ go to the concert instead.
A. must B. would C. should D. might
分析：根據(jù)B的回答：我不一定去，我有可能去聽音樂會。Might表示推測：可能。答案為D
8. A：I promise that she ____ get a nice present on her birthday.
B：Will it be a big surprise to her ?
A. should B. must C. would D. shall
分析：A說：“我答應她在生日聚會上她會得到一份生日禮物。shall表示許諾。答案為D
【模擬試題】
1. A：Is John coming by train ?
B：He should, but he _____ not. He likes driving his car.
A. must B. can C. need D. may
2. Mr. White _____ at 8:30 for the meeting, but he didn’t show up.
A. should have arrived B. should arrive
C. should have had arrived D. should be arriving
3. Sorry, I’m late. I _____ have turned off the alarm and gone to sleep again.
A. might B. should C. can D. will
4. You _____ be tired—You’ve only been working for an hour.
A. must not B. won’t C. can’t D. may not
5. —I didn’t go to work yesterday afternoon because my car broke down.
—You _____ mine. I wasn’t using it.
A. might borrow B. could have borrowed
C. can have borrowed D. ought to borrow
6. —A man answered the phone. I suppose it was her husband.
—It _____ her husband. He has been dead for ages.
A. mustn’t be B. couldn’t have been
C. may not have been D. mustn’t have been
【試題答案】
1. 分析：根據(jù)B的回答“他應該（坐火車來），但是也不一定，他喜歡開自己的車。本題考查了情態(tài)動詞的推測用法。may表示不十分有把握的推測。答案為D
2. 分析：根據(jù)句意：White先生本應該在8:30到這里出席會議的，可他（在8:30）沒有到場。Should have done表示：本應該。答案為A
3. 分析：本句是說話人在解釋遲到的原因：我或許是關掉鬧鐘又睡了。might have done 表示對過去的推測：可能已經(jīng)……答案為A
4. 分析：根據(jù)后半句You’ve only been working for an hour.（你才剛干了一個小時）說明
You _____ be tired（你不可能很累），can’t 表示“不可能”答案為C
5. 分析：聽到對方說“昨天車壞了而沒去上班”，第二個人說“你本來可以借我的車去
上班?！?本來可以/能：could have done. 答案為B
6. 分析：第二個人是說：那個人不可能是她丈夫，因為她丈夫已經(jīng)去世多年了。根據(jù)對
話的語境，是在談論過去的事，表示過去不可能：could not have done 答案為：B
知識重點：
情態(tài)動詞在表達推測意義的句子中的運用：
（一）用情態(tài)動詞表達事實的推測。can，could，might，may，must可以用來表達對事實的推測。根據(jù)說話人對事實的把握性大小，must表示“肯定…”，may / might / can / could表示“可能……”， must只用于肯定句中，may / might的否定式may not / might not表示 “可能不……”, 而can / could可以用于疑問句，表示“可能，可能……嗎?”，其否定式can’t / couldn’t 表示“不可能”。用情態(tài)動詞可以對現(xiàn)在或過去的事實進行推測。對不同的時間內(nèi)容推測有不同的結(jié)構(gòu)。
（二）對現(xiàn)在的事實進行推測：
主要結(jié)構(gòu)：…must / may / might +動詞原形
be+名詞/形容詞/介詞短語
be + doing
例句：
1. You must be Jeanne. I’m Mathilde Loisel. We used to know each other very well.
2. They must be in bed already at this time of the night.
3. The teacher must be joking.
4. Freda isn’t in class. She must be sick.
5. There must be something wrong.
6. She might be very clever, but she hasn’t got much common sense.
7. He may be arriving this evening.
8. He may be traveling around the world.
9. The keys can’t be in the room. I have just searched it very carefully.
10. Can the news be true ?
（三）對過去的事實進行推測：結(jié)構(gòu)：情態(tài)動詞+have done / been+名詞/形容詞/介詞短語
例句：
1. Mrs. Longmans must have been a pretty girl in her youth.
2. He couldn’t have seen Anna yesterday. She’s gone abroad.
3. I think I must have left my glasses in the library.
4. He might have overslept again.
5. Where can Tom have gone ?
情態(tài)動詞表達虛擬語氣：表達“本來…”，“不然早就…”。這是情態(tài)動詞的一種虛擬語氣用法。表示說話人所講的與所發(fā)生的事實相反。表達了說話人的埋怨，后悔的語氣。其結(jié)構(gòu)是在一些情態(tài)動詞后面加 have done 結(jié)構(gòu)。根據(jù)要表達的意思，有如下結(jié)構(gòu)：
should have done / ought to have done：本應該……
shouldn’t have done / oughtn’t to have done：本不該……
could have done：本來可以……
needn’t have done：本來沒必要……
would like to have done：本來很想……
would rather not have done: 本來不愿意……
could / might / have done: 不然早就……
例句：
1. You shouldn’t have laughed at his mistakes.
2. You could have told us earlier.
3. I ought to have bought that dictionary last week.
4. You ought not to have spent so much time in reading novels.
5. We need not have been in a tearing hurry to catch the train.
6. They would like to have seen that film last film.
7. If he had given me his number, I could have telephoned him.
8. They might have been frozen to death but for the rescue in time.
知識難點：
某些情態(tài)動詞的特殊用法：
need 和dare 的兩種形式的用法
need 和dare可以用做實義動詞，后面接不定式（to do）結(jié)構(gòu)，在疑問句和否定句中，加助動詞do/does/did/或don’t/doesn’t/didn’t。作為情態(tài)動詞使用時，主要用于疑問句和否定句中。情態(tài)動詞needn’t（沒有必要，不必）相當于don’t have to
例句：
1. It is cold, you need to wear some warm clothes.
2. Need I stay here with you for a while ? Thank you, you needn’t.
3. How dare you speak to parents like that ?
注意：
句型I dare say+從句。 意思是：我肯定…… = I’m sure或There is no doubt that+從句。
例句：
I dare say that my uncle will get the money if I die.
will和would
表示“意志”或“愿意”，would 則指過去愿意做……
例句：
1. He said that he would help us.
2. You may telephone if you will accept this job.
would可以表達“過去習慣做……”類似于“used to do”
例句：
1. When we were children, we would go swimming every summer in that river.
表示請求，固定的句型：Will/Would you please do…? / Would you like to do…?
例句：Will/Would you please give him a message when you see him ?
shall
1. 用于第一，三人稱，表示“請求”；“建議” 或“推薦”
例句：
1. Shall we start the meeting now?
2. Shall I watch TV now ?
3. Shall my son carry the case for you ?
2. 用于第二人稱，表示“命令，“要求”，“許諾”
例句：
1. You shall take whatever you like.
2. You shall not go to the party with me if you make so much noise again.
在表示推測的否定句或疑問句中，常用can /can’t /could / couldn’t表示，意思是：“可能…嗎?”；“…不可能…”。而不能使用mustn’t或must等詞。
【典型例題】
1. —Do you think he will do me a favor ?
—As far as I know, he is the last one to help others. He _____ be prepared to give you a hand, though.
A. might B. must C. can D. should
分析：本題考查情態(tài)動詞推測性用法。 根據(jù)he is the last one to help others.（他是最不可能幫助別人的人），既然如此，那么“幫助你”的可能性也就最小了。 答案為A
2. —Look, someone is coming. Guess who it ____ be ?
—I think it ___ be Tom.
—I don’t think it ___ be ____ .
A. can ; must ; can ; he B. may ; can ; must ; him
C. must ; can ; must ; his D. might ; must ; can ; himself
分析：根據(jù)備選答案。 can表示推測時用于疑問句或否定句中。本題首句就應該是Guess who can it be? 第二句應該是I think it must be Tom.（說話人十分肯定）。第三句表達了說話人對前一個人的否定。即：I don’t think it can be him/he.（不可能是他）。答案為A
3. —Do you know Ms. Wang likes walking after supper ?
—Sure. She ____ around the campus now.
A. must be walking B. must walk
C. may walk D. may be walking
分析：關鍵詞Sure告訴我們說話人的口氣十分肯定。根據(jù)句子語境：她此刻肯定正在校園散步呢。must be doing表示肯定正在做。答案為A
4. —I stayed at a hotel in New York.
—Oh, did you ? You _____ with Barbara.
A. could have stayed B. could stay C. would say D. must have stayed
分析：首句說：我在紐約住在一家賓館里。在此a hotel是泛指。所以D選項不合題意。第二句在說：你本來可以和Barbara.住在一起的。Could have done表示：本來可以。答案為A
5. Why didn’t you tell me there was no meeting today ? I _____ all the way here through the heavy snow.
A. needn’t have driven B. can’t have driven
C. mustn’t have driven D. shouldn’t have driven
分析：根據(jù)句意：你為什么不告訴我今天沒有會？我本來沒必要冒著大雪開車跑這么多路。Needn’t have done表示本來沒必要。答案為A
6. I was really anxious about you. You _____ home without a word.
A. mustn’t leave B. shouldn’t have left
C. couldn’t have left D. needn’t leave
分析：根據(jù)句意：我真的很擔心你，你真不應該一句話都不說就離開家?！半x開家”已經(jīng)發(fā)生了。Should have done正好表達了本句的意思。答案為B
7. A：Are you coming to Jeff’s party ?
B：I’m not sure. I _____ go to the concert instead.
A. must B. would C. should D. might
分析：根據(jù)B的回答：我不一定去，我有可能去聽音樂會。Might表示推測：可能。答案為D
8. A：I promise that she ____ get a nice present on her birthday.
B：Will it be a big surprise to her ?
A. should B. must C. would D. shall
分析：A說：“我答應她在生日聚會上她會得到一份生日禮物。shall表示許諾。答案為D
【模擬試題】
1. A：Is John coming by train ?
B：He should, but he _____ not. He likes driving his car.
A. must B. can C. need D. may
2. Mr. White _____ at 8:30 for the meeting, but he didn’t show up.
A. should have arrived B. should arrive
C. should have had arrived D. should be arriving
3. Sorry, I’m late. I _____ have turned off the alarm and gone to sleep again.
A. might B. should C. can D. will
4. You _____ be tired—You’ve only been working for an hour.
A. must not B. won’t C. can’t D. may not
5. —I didn’t go to work yesterday afternoon because my car broke down.
—You _____ mine. I wasn’t using it.
A. might borrow B. could have borrowed
C. can have borrowed D. ought to borrow
6. —A man answered the phone. I suppose it was her husband.
—It _____ her husband. He has been dead for ages.
A. mustn’t be B. couldn’t have been
C. may not have been D. mustn’t have been
【試題答案】
1. 分析：根據(jù)B的回答“他應該（坐火車來），但是也不一定，他喜歡開自己的車。本題考查了情態(tài)動詞的推測用法。may表示不十分有把握的推測。答案為D
2. 分析：根據(jù)句意：White先生本應該在8:30到這里出席會議的，可他（在8:30）沒有到場。Should have done表示：本應該。答案為A
3. 分析：本句是說話人在解釋遲到的原因：我或許是關掉鬧鐘又睡了。might have done 表示對過去的推測：可能已經(jīng)……答案為A
4. 分析：根據(jù)后半句You’ve only been working for an hour.（你才剛干了一個小時）說明
You _____ be tired（你不可能很累），can’t 表示“不可能”答案為C
5. 分析：聽到對方說“昨天車壞了而沒去上班”，第二個人說“你本來可以借我的車去
上班?！?本來可以/能：could have done. 答案為B
6. 分析：第二個人是說：那個人不可能是她丈夫，因為她丈夫已經(jīng)去世多年了。根據(jù)對
話的語境，是在談論過去的事，表示過去不可能：could not have done 答案為：B