1、七、混沌不清的情态动词和亦真亦假的虚拟语气 诊断与对策一轮诊断.用括号内的词改写句子，使其与前一句有相似的意义1.I suggest we take a taxi.(could)_2.Its possible that Louise is waiting for us at the airport.(may)_3.Its impossible for the story to be true.(cant)_We could take a taxi.Louise may be waiting for us at the airport.The story cant be true.4.Im to
2、o scared to go up on the roof.(dare)_5.We expect the parcel to arrive soon.(should)_6.At one time I played tennis regularly.(used)_I darent go up on the roof.The parcel should arrive soon.I used to play tennis regularly.单项填空1.To relax，Maja _ often watch the dolphins play at an aquarium(水族馆)near her
3、home.(2011湖北完形，43)A.might B.shouldC.could D.would解析 句意为：为了放松一下，Maja 过去经常在她家附近的水族馆里看海豚表演。would 此处用于指过去经常发生的事情。D 2.There are also styles to remind me of Muma tiny chair which _ be in her bedroom is set in one room.(2011四川完形，37)A.ought to B.used toC.might D.could解析 句意为：也有一些房间的风格让我想起了我的母亲其中一个房间里就摆放了母亲卧室
4、里曾摆放过的一把小椅子。ought to 应该；used to 过去常常；might可能；could 可能，能够。根据句意可知 B 项正确。B 3.I didnt know Moms _ be lawyers too.(2011天津完形，23)A.must B.ought toC.need D.could解析 句意为：我当时不知道妈妈也可能成为律师。must 一定；ought to 应该；need 需要；could 可能，能够。根据句意可确定 D 项正确。D 4.Pity you missed the lecture on nuclear pollution.I _it，but I was b
5、usy preparing for a job interview.(2011福建，34)A.attended B.had attendedC.would attend D.would have attended解析 句意为：你错过了关于核污染的讲座真是遗憾。我本想去听的，但我忙着准备工作面试。由语境可知，此处表示“本想去而事实上没去”，为虚拟语气。叙述与过去事实相反的情况要用 would have done，故 D 项正确。D 5.Maybe if I _ science，and not literature then，I would be able to give you more hel
6、p.(2011北京，30)A.studied B.would studyC.had studied D.was studying解析 句意为：或许如果当初我学习理科而不是文学的话，我(现在)就能给你更多的帮助。这是错综时间条件句，从句与过去事实相反，主句与现在事实相反，故从句用过去完成时。C 备考策略1.体会说话者的语气和态度，注意情态动词的区别。情态动词表示说话者的态度和语气。解答情态动词类的题目时，一定要细细领会情景特征，体会说话者的语气，情景中没有废话，不要放过任何细节。只有这样，才会找到有效信息，做出最佳选择。2.体会时间概念，掌握“情态动词have done”的用法。“情态动词hav
7、e done”是对过去发生的情况进行判断，要区分时态和情态动词的概念。而且多数题目在语境中考查知识点，做这类题目时要注意动词的形式以及语气要和语境一致。3.掌握虚拟语气规律，使用正确的表达形式。虚拟语气通常用在一些特定的句型中，在 advise，demand，order，request，propose，require，recommend 等的宾语从句中要用虚拟语气，即谓语动词用“(should)动词原形”的形式。同时我们要注意在这些动词的同根名词后的表语从句或同位语从句中也要使用虚拟语气。4.分析虚拟条件句，掌握虚拟语气在条件句中的用法。虚拟条件句的表现形式非常灵活，有时省略连词 if，把从句
8、中的 were，had 或 should 提前；有时用 without，but for等介词短语来表示。有时候条件状语从句中的动作和主句中的动作发生的时间不一致，这时动词的形式要根据它所表示的时间加以调整。考点与考题考点一 情态动词表推测1.表示肯定推测时 must will would ought to should can could may might。2.表示否定推测时 cant 语气最强，意为“不可能”，may/might/could not 的语气较弱，意为“可能不”。(mustnt 不表示否定推测，而表示“禁止，不能”。)3.表示推测时，must 只能用在肯定句中，may 和 m
9、ight 只能用在肯定句和否定句中，can 和 could 可用于各种句式，can 用于肯定句中时，有时表示“一时的可能性或暂时的可能性”。4.“情态动词do”表示对目前动作的推测；“情态动词be doing”表示对正在发生的动作的推测；“情态动词have done”表示对过去发生的动作的推测。根据句子情景或汉语提示完成句子1.That cant(不可能)be Lily；she is in China.2.I might/may go to China next year，but Im not sure.考题印证1.It _ be the postman at the door.Its onl
10、y six oclock.(2011江西，23)A.mustnt B.cantC.wont D.neednt解析 句意为：现在才 6 点，门口的人不可能是邮递员。表达“不可能”，用 cant。B 2.I dont really like James.Why did you invite him?Dont worry.He _ come.He said he wasnt certain what his plans were.(2011北京，24)A.must not B.need notC.would not D.might not解析 根据“He said he wasnt certain
11、what his plans were.”可知，他来的把握性不大，故 might not“或许不”符合题意。D 3.“You_have a wrong number，”she said.“Theres no one of that name here.”(2010浙江，17)A.need B.can C.must D.would解析 句意为：“你一定弄错了号码，”她说，“这儿没人叫那个名字。”need 需要；can 能，可以；must一定，必须；would 要，会。由语境可知，空格处的词对目前的情况作出肯定判断，故用 must。can 表推测用于否定句、疑问句中。C 考点二“情态动词have
12、done”用法总结1.must have done 表示对过去情况的肯定猜测，意为“准是(一定)了”。2.may/might have done 用于肯定句和否定句，表示对过去情况发生的可能性的不确定猜测，意为“可能/也许(已经)了”；might have done 还可表示对过去没有做成某事的遗憾或责备，意为“本可以”。3.can/could have done 用于否定句和疑问句，表示对过去情况发生的可能性的否定或质疑，分别意为“不可能/不会(已经)了”和“可能/也许(已经)了”；could have done 还可表示对过去本来能够完成但却未能完成之较婉转的批评或对过去情况含有不满情绪的
13、提议，意为“本来能够的”。4.should/ought to have done 表示对过去没有做某事的遗憾、后悔甚至责备等情绪，意为“本该的(但没有)”，其否定式意为“本不该(但却做了)”。5.neednt have done 表示过去已经做了不必要做的事，意为“本来没必要做”。6.对“情态动词have done”结构的简略回答要用“情态动词have”。You ought to have called her yesterday.Yes，I know I ought to have.根据句子描述的情景选词填空1.What a pity.Considering his ability and
14、experience，he might(need/must/can/might)have done better.2.As it turned out to be a small house party，we neednt(couldnt/neednt/mustnt)have dressed up so formally.考题印证1.Jack described his father，who _a brave boy many years ago，as a strong-willed man.(2010安徽，32)A.would be B.would have beenC.must beD.m
15、ust have been解析 句意为：杰克把多年以前一定是个勇敢男孩的父亲描述成为一个意志坚强的人。must have been 是对过去事实的肯定猜测；must be 是对现在事实的肯定猜测；would be 是过去将来时；would have been 是虚拟语气，故选 D 项。D 2.They _ have arrived at lunchtime but their flight was delayed.(2011新课标全国卷，32)A.will B.canC.must D.should解析 句意为：他们本应该在午饭时间到达，但是航班延误了。表达“过去应该做某事(而实际上未做)”，用
16、 should have done 结构。D 3.Mark_have hurried.After driving at top speed，he arrived half an hour early.(2010天津，9)A.neednt B.wouldntC.mustnt D.couldnt解析 句意为：马克本没有必要那么急，全速开车后他提前了半个小时到达。根据句意和前后的照应可知应选 A 项。A 项表示“本没有必要”；B 项意为“不会”；C 项表示“不允许”；D 项表示“不可能”。显然，B、C、D 三项与后文论述不符。A 4.I left my handbag on the train，bu
17、t luckily someone gave it to a railway official.How unbelievable to get it back!I mean，someone _ it.(2011江苏，34)A.will have stolen B.might have stolenC.should have stolen D.must have stolen解析 might have done 在此表达“可能”，表示对过去发生之事的不太肯定的推测，符合题意。B 考点三 关于情态动词应注意的两个问题1.含有情态动词的疑问句的答语(1)回答由 need 引起的问句，肯定回答用 mu
18、st，否定回答用 neednt 或 dont have to。(2)回答由 must 引起的问句，肯定回答用 must，否定回答用 neednt 或 dont have to。(3)回答由 may 引起的问句，肯定回答用 may，否定回答用 cant 或 mustnt。(4)回答由 could 引起的表示请求的疑问句时，肯定回答用 can，否定回答用 cant 或 couldnt。2.need 和 dare 作为情态动词和实义动词(1)作情态动词时，dare 主要用于否定句和疑问句以及条件句中(在简略回答中可用于肯定句)；need 一般用于否定句或疑问句中，不用于肯定句。(2)作实义动词时，d
19、are，need 都有人称、数和时态的变化，注意 dare 后接动词不定式时，符号 to 可以省略。做有关这两个情态动词的练习时，首先要分清它们是情态动词还是实义动词。完成句子1.Need I tell you all the details？Yes，you must.2.She darent say a word，dare she(是吗)?考题印证1.May I take this book out of the reading room?No，you _.You read it in here.(2010陕西，23)A.mightnt B.wontC.neednt D.mustnt解析 考
20、查情态动词。英语中用 could，might 表示询问或征求意见，肯定性应答要用 can 或 may 来代替 could或 might；而 may 或 might 征求意见的问句否定应答时要用 mustnt，故本题选 D。D 2.Could I use your bike while you are out?Of course you _.A.couldB.shouldC.mustD.can解析 句意为：你不在时我能用一下你的自行车吗？当然可以。以 could 开头的问句征求对方意见时，肯定回答用 can，否定回答用 cant 或 couldnt。D 3.The room is so dirt
21、y._ we clean it?Of course.A.Will B.ShallC.Would D.Do解析 shall 用于一、三人称的疑问句中，表示征求对方意见。根据答语“Of course.”可判断出对方在征求意见，“我们打扫一下好么？”，故选 B。另外，shall用于二、三人称的陈述句中，表示命令、强制、决心、允诺、警告等。B 4.I _ worry about my weekendI always have my plans ready before it comes.(2011上海，28)A.cant B.mustntC.darent D.neednt解析 句意为：我没必要担心我的
22、周末，我总是提前把计划制订好。表达“没必要”用 neednt。D 考点四 含蓄条件句的几种类型1.将条件隐含在不定式短语中To have studied harder，you would have passed the examination.2.将条件隐含在分词短语中Born in better times，he would have been a scholar.3.将条件隐含在名词短语中A few hours earlier，and you would have seen the famous writer.4.将条件隐含在定语从句中Anyone who has seen that pa
23、inting might have taken it for a photo.5.将条件隐含在一定的上下文中Dont bother to read all these papers.It would take too long.6.将条件隐含在形容词及其比较级中A more careful person would not have made so many mistakes.7.用 with，without，but for，under，or，otherwise，if only等代替条件状语从句But for the storm，I would have arrived much earlie
24、r.考题印证1.We _ Johns name on the race list yesterday but for his recent injury.(2011江西，28)A.will put B.will have putC.would put D.would have put解析 句中 but for 意为“要不是”，表示与过去事实相反的假设，故只能用 would have done 结构。D 2.I _ through that bitter period without your generous help.(2011陕西，22)A.couldnt have goneB.didnt
25、 goC.wouldnt goD.hadnt gone解析 句意为：没有你的慷慨帮助，我不可能熬过那段痛苦的日子。由 without your generous help 可知，此处考查的是与过去事实相反的虚拟语气，故答案为 A。A 3.He hesitated about the brake，otherwise the accident _.A.could have been avoidedB.could have avoidedC.would have avoidD.should have been avoided解析 accident 与 avoid 之间为动宾关系，排除 B、C 两项；
26、此处 otherwise 为隐含的虚拟条件句，相当于 if he hadnt hesitated about the brake，根据句意可知 A 项正确。A 4.Did you hear Tom was criticized for his spelling mistakes in his English composition?Yes，but a more careful person _ so many mistakes.A.wouldnt make B.neednt have madeC.shouldnt make D.wouldnt have made解析 由语境可知此处表示过去，A
27、、C 两项可以排除；B 项意为“本没有必要做某事”，不符合语境，故选D 项，表虚拟。D 题点与题组命题点 情态动词表推测1.Hi，Tom.Any idea where Jane is?She _ in the classroom.I saw her there just now.A.shall be B.should have beenC.must be D.might have been解析 根据第二句话“她一定在教室里，我刚才看见她在那儿”可知，这是对现在事实的把握性较大的肯定推测，故用 must。C 2.The traffic is heavy now，so Mike _ come la
28、te.Lets wait ten more minutes.A.can B.need C.may D.shall解析 由语境知，此处表“可能，或许”，可能性较小，用 may。C 3.There _ be any difficulty in passing the oral test since you have practiced a lot in the school.A.mustnt B.shantC.shouldnt D.neednt解析 shouldnt“不应该”，表推测潜在的可能性。C 4.Oh，its so cool in the house.You _ have turned o
29、n the air conditioner，havent you？A.shouldB.might C.must D.can解析 句意为：噢，屋里真凉快。你肯定开了空调，对吗？should have done“本应该做某事而没做”；might have done“过去可能做过；过去本可能做而事实上没做”；must have done“过去肯定做过”；can have done“过去可能做过”。由语境可知此处应选 must have done。C 5.She _ have left school，for her bike is still here.A.cant B.wouldntC.shouldnt D.neednt解析 cant have done“不可能做过”；wouldnt have done“不会做过”；shouldnt have done“本不应该做某事而事实上已经做了”；neednt have done“本没必要做某事”。由句意可知 A 项正确。A 返回
