高考英語語法：情態動詞用法講解
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英語備考
情態動詞有一定的詞義, 表示某種感情或語氣, 是不完全動詞, 不能單獨作謂語, 需和實義動詞一起構成謂語. 常見的情態動詞有: can / could, may / might, must, shall / should, will / would, need, ought to, dare / dared等
一.may / might的用法:
1.表示“可以”, 即表示說話人許可或請求許可
a. You may take it away.
b. May I come in ?
2.表示“可能, 也許” (在疑問句中通常不用may / might, 而用likely, do you think, can等表示“是否可能, 會不會”的意思)
a. He may come today.
b. Is it likely to rain ?
c. Do you think the train will be late ?
d. Can the news be true ?這消息會是真的嗎?
3.在提建議時, 可用May I … ?
a. May I carry your bag ?
b. May I make a suggestion ?
二.can / could的用法:
1.表示許可或請求許可, 相當于may. 但can比may用得更廣泛. can不僅表示說話人同意, 準許, 還可以表示客觀條件許可. may通常只表示說話人同意或準許
a. The class is over. You can go home now.
b. You can go there tomorrow.
c. Can I borrow your car for today ?
2.在提建議時, 可用Can I / you… ?
a. Can I buy you a drink ?
3.表示“會, 能”, 相當于be able to
a. He can speak English.
b. Can you play tennis ?
c. Little Tom can’t move the big box.
4.在疑問句中表示懷疑, 不確定或不會有的情況, 即“否定的推測”
a. Can it be true ? 這是真的嗎?
b. Can it be true that he has passed the exam ? 他真的通過考試了嗎?
5.can’t / couldn’t在陳述句中可表示“肯定不, 一定不”的意思
a. He can’t be in the room right now.
b. It can’t have rained last night, for the ground is dry.
6.can’t / couldn’t help doing sth表示“不得不,忍不住做某事”
a. People couldn’t help laughing at the foolish emperor.
7.can / be able to do的區別:
①.be able to可用于各種時態, 而can只有現在時can和過去時could
②.be able to可以和另一個不完全動詞連用, 如should be able to (應該能夠), must be able to (必須能夠)等, 而can則不可以這樣用
③.強調“能力”時, 多用be able to
a. The patient was soon able to sit up and read.
④.can可用于人或其他事物作主語的句子中; be able to只用于有生命的名詞或代詞作主語的句子中
三.must的用法:
1.表示“必須”, 它的否定形式是need not / needn’t, 而不是must not / mustn’t, mustn’t表示禁止或不許做某事
a. You must set off at once.
b. You needn’t tell John about it.
c. You mustn’t play with fire.
2.表示“肯定是, 一定是”的推測意義; 與此對應, 表示“肯定不,一定不”用can’t, 而不用mustn’t
a. You must be very tired now.
b. If he had really been there, I must have seen him.
c. He must have gone away. We don’t see him anywhere.
3.must / have to的區別:
①.must / have to一般可以通用, 但must側重于說話人主觀上的看法, 即“說話人認為必須”; have to側重于客觀上的需要, 含有“客觀上不得不”之意
a. If the person is not breathing, you must try to start his breathing.
b. You must / have to study with a teacher if you want to know how to do first aid.
②.must沒有時態的變化, 一般用于表示現在或將來; have to有時態的變化, 可用于過去, 現在, 將來各種時態
a. We must study hard when we are young.
b. I think she must remain in hospital for a week.
c. We had to stay there for a whole day because of the rain.
d. We have to practise a lot if we want to speak English well.
e. The situation has changed; we will have to change our plan.
③.它們的否定式mustn’t / not have to有很大的不同: mustn’t表示“不要(做某事)”, 有禁止之意; not have to表示“不必要(做某事)”, 含有“客觀上無此必要”之意
a. You mustn’t move a person if he is badly hurt.
b. You don’t have to be a doctor to do first aid.
四.would的用法:
1.表示主觀意志和愿望, 即“愿意,想要”
a. Come here whenever you would.
b. He would not leave before he finished his work.
2.would do sth可以表示過去經常發生的動作, 相當于used to do sth
a. When we were children we would go swimming every summer.
b. On Sundays he would go fishing for hours when he lived in the countryside.
3.表示請求, 愿望, 語氣客氣, 委婉
a. I would like some tea.
b. Would you mind closing the door ?
c. Would you tell me something about your trip ?
4.表示推測, 表示“大概, 也許”的意思
a. That would be the pen you are looking for.那也許是你在找的筆吧
五.should的用法:
1.表示義務, 責任, 可譯為“應當”
a. We should complete the text in time.
b. You should be so careless.
2.表示推測或推論, 可譯為“可能, 應該是”
a. He should be home by now, I think.
b. He should have arrived in Nanjing by this time.
3.should / ought to的區別:
should / ought to一般可以通用. should側重于說話人主觀上的看法, 有時含有勸告, 建議的口氣, 即 “按我的想法應該如何”; ought to語氣更強, 強調“有責任, 有義務做某事”或者 “按道理應該如何”
a. “I will start the work at once.” “I think you should start at once.”
b. “I will start the work tomorrow.” “No. You ought to start at once.”
六.need的用法: need表示“需要”, 既可作為情態動詞, 也可作實義動詞
1.need作實義動詞時, 注意以下用法:
①.need to do sth; ②.need sb to do sth; ③.need doing sth (主動形式表被動意義)
a. You need to remain in bed.
b. I need you to help me with the housework.
c. The garden needs watering.( =The garden needs to be watered.)
2.need作情態動詞時, 多用于否定句及疑問句中, 不用于肯定句中
a. It is still early. You needn’t hurry. =You don’t need to hurry.
b. It is 11 o’clock. Need I go now? =Do I need to go now ?
3.對于用need的提問, 肯定回答用must, 否定回答用needn’t
a. Need I come? Yes, you must. / No, you needn’t.
七.dare / dared的用法: 表示 “敢”, 既可作為情態動詞, 也可作為實義動詞
1.作為情態動詞時, 主要用于否定句和疑問句中, 不用于肯定句中
a. Little Jane dared not go alone. =Little Jane didn’t dare to go alone.
b. Dare you go out alone at night ? =Did you dare to go out alone at night ?
2.作為實義動詞時, 可用于: dare to do sth
a. Little Jane didn’t dare to go alone.
b. Did you dare to go out alone at night ?
一.may / might的用法:
1.表示“可以”, 即表示說話人許可或請求許可
a. You may take it away.
b. May I come in ?
2.表示“可能, 也許” (在疑問句中通常不用may / might, 而用likely, do you think, can等表示“是否可能, 會不會”的意思)
a. He may come today.
b. Is it likely to rain ?
c. Do you think the train will be late ?
d. Can the news be true ?這消息會是真的嗎?
3.在提建議時, 可用May I … ?
a. May I carry your bag ?
b. May I make a suggestion ?
二.can / could的用法:
1.表示許可或請求許可, 相當于may. 但can比may用得更廣泛. can不僅表示說話人同意, 準許, 還可以表示客觀條件許可. may通常只表示說話人同意或準許
a. The class is over. You can go home now.
b. You can go there tomorrow.
c. Can I borrow your car for today ?
2.在提建議時, 可用Can I / you… ?
a. Can I buy you a drink ?
3.表示“會, 能”, 相當于be able to
a. He can speak English.
b. Can you play tennis ?
c. Little Tom can’t move the big box.
4.在疑問句中表示懷疑, 不確定或不會有的情況, 即“否定的推測”
a. Can it be true ? 這是真的嗎?
b. Can it be true that he has passed the exam ? 他真的通過考試了嗎?
5.can’t / couldn’t在陳述句中可表示“肯定不, 一定不”的意思
a. He can’t be in the room right now.
b. It can’t have rained last night, for the ground is dry.
6.can’t / couldn’t help doing sth表示“不得不,忍不住做某事”
a. People couldn’t help laughing at the foolish emperor.
7.can / be able to do的區別:
①.be able to可用于各種時態, 而can只有現在時can和過去時could
②.be able to可以和另一個不完全動詞連用, 如should be able to (應該能夠), must be able to (必須能夠)等, 而can則不可以這樣用
③.強調“能力”時, 多用be able to
a. The patient was soon able to sit up and read.
④.can可用于人或其他事物作主語的句子中; be able to只用于有生命的名詞或代詞作主語的句子中
三.must的用法:
1.表示“必須”, 它的否定形式是need not / needn’t, 而不是must not / mustn’t, mustn’t表示禁止或不許做某事
a. You must set off at once.
b. You needn’t tell John about it.
c. You mustn’t play with fire.
2.表示“肯定是, 一定是”的推測意義; 與此對應, 表示“肯定不,一定不”用can’t, 而不用mustn’t
a. You must be very tired now.
b. If he had really been there, I must have seen him.
c. He must have gone away. We don’t see him anywhere.
3.must / have to的區別:
①.must / have to一般可以通用, 但must側重于說話人主觀上的看法, 即“說話人認為必須”; have to側重于客觀上的需要, 含有“客觀上不得不”之意
a. If the person is not breathing, you must try to start his breathing.
b. You must / have to study with a teacher if you want to know how to do first aid.
②.must沒有時態的變化, 一般用于表示現在或將來; have to有時態的變化, 可用于過去, 現在, 將來各種時態
a. We must study hard when we are young.
b. I think she must remain in hospital for a week.
c. We had to stay there for a whole day because of the rain.
d. We have to practise a lot if we want to speak English well.
e. The situation has changed; we will have to change our plan.
③.它們的否定式mustn’t / not have to有很大的不同: mustn’t表示“不要(做某事)”, 有禁止之意; not have to表示“不必要(做某事)”, 含有“客觀上無此必要”之意
a. You mustn’t move a person if he is badly hurt.
b. You don’t have to be a doctor to do first aid.
四.would的用法:
1.表示主觀意志和愿望, 即“愿意,想要”
a. Come here whenever you would.
b. He would not leave before he finished his work.
2.would do sth可以表示過去經常發生的動作, 相當于used to do sth
a. When we were children we would go swimming every summer.
b. On Sundays he would go fishing for hours when he lived in the countryside.
3.表示請求, 愿望, 語氣客氣, 委婉
a. I would like some tea.
b. Would you mind closing the door ?
c. Would you tell me something about your trip ?
4.表示推測, 表示“大概, 也許”的意思
a. That would be the pen you are looking for.那也許是你在找的筆吧
五.should的用法:
1.表示義務, 責任, 可譯為“應當”
a. We should complete the text in time.
b. You should be so careless.
2.表示推測或推論, 可譯為“可能, 應該是”
a. He should be home by now, I think.
b. He should have arrived in Nanjing by this time.
3.should / ought to的區別:
should / ought to一般可以通用. should側重于說話人主觀上的看法, 有時含有勸告, 建議的口氣, 即 “按我的想法應該如何”; ought to語氣更強, 強調“有責任, 有義務做某事”或者 “按道理應該如何”
a. “I will start the work at once.” “I think you should start at once.”
b. “I will start the work tomorrow.” “No. You ought to start at once.”
六.need的用法: need表示“需要”, 既可作為情態動詞, 也可作實義動詞
1.need作實義動詞時, 注意以下用法:
①.need to do sth; ②.need sb to do sth; ③.need doing sth (主動形式表被動意義)
a. You need to remain in bed.
b. I need you to help me with the housework.
c. The garden needs watering.( =The garden needs to be watered.)
2.need作情態動詞時, 多用于否定句及疑問句中, 不用于肯定句中
a. It is still early. You needn’t hurry. =You don’t need to hurry.
b. It is 11 o’clock. Need I go now? =Do I need to go now ?
3.對于用need的提問, 肯定回答用must, 否定回答用needn’t
a. Need I come? Yes, you must. / No, you needn’t.
七.dare / dared的用法: 表示 “敢”, 既可作為情態動詞, 也可作為實義動詞
1.作為情態動詞時, 主要用于否定句和疑問句中, 不用于肯定句中
a. Little Jane dared not go alone. =Little Jane didn’t dare to go alone.
b. Dare you go out alone at night ? =Did you dare to go out alone at night ?
2.作為實義動詞時, 可用于: dare to do sth
a. Little Jane didn’t dare to go alone.
b. Did you dare to go out alone at night ?