2022年情态动词的基本用法归纳.docx

精选学习资料 - - - - - - - - - 情态动词的基本用法归纳情态动词有 can could, may might, must, have to, shall should, will would, dare dared, need needed, ought to 等；词原形构成谓语；一、 can, could 情态动词无人称和数的变化；不能单独使用,必需与其后的动1 表示才能（体力、学问、技能）；Can you lift this heavy box. （体力）Mary can speak three languages.（学问）Can you skate.（技能）此时可用 be able to 代替； Can 只有一般现在时和一般过去式；时态；I ll not be able to come this afternoon.而 be able to 就有更多的当表示 “ 经过努力才得以做胜利某事” 时应用 be able to ,不能用 Can；如：He was able to go to the party yesterday evening in spite of the heavy rain. 2 表示恳求和答应；-Can I go now. - Yes, you can. / No, you cant.此时可与 may 互换；在疑问句中仍可用 婉,不能用于确定句和答语中；- Could I come to see you tomorrow. could,might 代替,不是过去式,只是语气更委- Yes, you can. No, Im afraid not. 3 表示客观可能性（客观缘由形成的才能）；Theyve changed the timetable, so we can go by bus instead.This hall can hold 500 people at least. 4 表示估量（惊奇、怀疑、不信任的态度）Can this be true. This can t be done by him. How can this be true. 二、 may, might ,用于疑问句、否定句和感叹句中；1 表示恳求和答应；might 比 may 语气更委婉,而不是过去式；否定回答时可用cant或 mustnt,表示 “不行以,禁止 ” ；-Might/ May I smoke in this room. - No, you mustn t.- May/Might I take this book out of the room. - Yes, you can. No, you cant / mustnt. 用 May I.？征徇对方许可时比较正式和客气,而用 2）用于祈使句,表示希望；May you succeed. 3 表示估量、可能性（不用于疑问句）；Can I.？在口语中更常见；might 不是过去式,它所表示的可能性比 may 小；1He may /might be very busy now. 2Your mother may /might not know the truth. 名师归纳总结 - - - - - - -第 1 页,共 4 页精选学习资料 - - - - - - - - - 三、 must, have to 1 表示必需、必要；You must come in time. 在回答引出的问句时,假如是否定的, 不能用 mustnt（禁止,不准）,而用 neednt, don t have to（不必） . - Must we hand in our exercise books today. - Yes, you must. - No, you don t have to / you neednt.而 have to 就强调客观需要； Must 只有一般现在时,have 2 must 是说话人的主观看法,to 有更多的时态形式；1 he play isnt interesting, I reall y must go now. 2 I had to work when I was your age. 3 表示估量、可能性（只用于确定的陈述句）1 Youre Toms good friend, so you must know what he likes best.2 Your mother must be waiting for you now. 四、 dare, need 1 dare 作情态动词用时, 常用于疑问句、否定句和条件从句中, 过去式形式为dared；1 How dare you say Im unfair.2 He daren t speak English before such a crowd, dare he.3 If we dared not go there that day , we couldn t get the beautiful flowers.2 need 作情态动词用时, 常用于疑问句、否定句；在确定句中一般用must, have to, ought to, should 代替；1You neednt come so early.2. - Need I finish the work today. - Yes, you must. / No, you neednt.有人称、时态和数的变化；在确定句中,dare 后面 3 dare 和 need 作实义动词用时,常接带 to 的不定式； 在疑问句和否定句中,dare 后面可接带 to 或不带 to 的不定式； 而 need 后面只能接带 to 的不定式；1. I dare to swim across this river. 2. He doesnt dare to answer.五、 shall, should 1 shall 用于第一人称,征求对方的看法；What shall we do this evening. 2 shall 用于其次、三人称,表示说话人给对方的命令、警告、承诺或威逼；1. You shall fail if you dont work hard.2. He shall have the book when I finish it. 承诺 3. He shall be punished.威逼 六、 will, would 1 表示恳求、建议等,would 更委婉；Will / Would you pass me the ball, please. 2 表示意志、愿望和决心；1. I will never do that again. 2. They asked him if he would go abroad. 名师归纳总结 3 would 表示过去反复发生的动作或某种倾向；would 表示过去习惯时比used to 正式,第 2 页,共 4 页- - - - - - -精选学习资料 - - - - - - - - - 且没有 “现已无此习惯 ” 的含义；1. During the vacation, he would visit me every other day. 2. The wound would not heal. 4 表示估量和猜想；It would be about ten oclock when she left home.七、 should, ought to 1 should, ought to 表示 “应当 ”,ought to 表示义务或责任,比 1. I should help her because she is in trouble. 2. You ought to take care of the baby. should 语气重；2 表示劝说、建议和命令；should, ought to 可通用,但在疑问句中常用should；1. You should / ought to go to class right away. 2. Should I open the window. 3 表示估量 should , ought to 客观估量 , must主观估量 ；1.He must be home by now. 确定他已到家 2.He ought to/should be home by now. 不太确定 3. This is where the oil must be. 直爽 含蓄 4. This is where the oil ought to/should be. 八、 情态动词 +不定式完成式（have done）1 can / could + have done 在确定句中表示“ 原来可以做而实际上能做某事” ,是虚拟语 气；在疑问句或否定句中表示对过去行为的怀疑或不愿定 , 表示估量；1. You could have done better, but you didnt try your best. （虚拟语气）2. He can t have been to that town.（估量）3. Can he have got the book.（估量）have done）2 may / might + 不定式完成式（表示对过去行为的估量；不能用于疑问句中,没有虚拟语气的用法；Might 所表示的可 能性比 may 小；1. He may not have finished the work . 2. If we had taken the other road, we might have arrived earlier. can 3）must +不定式完成式（have done）can,用于确定句中,表示对过去行为的估量；意为“ 肯定、想必 ” ；其疑问、否定形式用t代替；参看1 can / could + have done 表示估量；1. You must have seen the film Titanic. 2. He must have been to Shanghai. 4）should +不定式完成式（have done）用于确定句中,表示对过去行为的估量；He should have finished the work by now ；名师归纳总结 表示 “本应当做而实际上没有做某事” ,其否定式表示某种行为本不该发生却发生了；可第 3 页,共 4 页以与 ought to + 不定式完成式（have done）互换；1. You ought to / s hould have helped him. but you didnt.2. She shouldn t have taken away my measuring tape, for I wanted to use it.5 needn t + 不定式完成式（have done）表示 “原来不必做而实际上做了某事” ；You neednt have watered the flowers, for it is going to rain.- - - - - - -精选学习资料 - - - - - - - - - 6 will +不定式完成式（have done）主要用于其次、三人称,表示对已完成的动作或事态的估量；He will have arrived by now. 名师归纳总结 - - - - - - -第 4 页,共 4 页