第二部分第九讲情态动词和虚拟语气

第九讲　情态动词和虚拟语气 情态动词的5个基本用法 1．表能力 (1)表示现在的能力： can, am/is/are able to (2)表示将来的能力： will be able to (3)表示过去的能力： could表示过去的能力， 不表示是否成功地做了； was/were able to表示过去有能力做而且成功地做了 I’m going to Europe on vacation together with John if I can find the money. 如果我能找到足够的金钱， 我将和约翰一起去欧洲度假。 2．表推测 (1)肯定句： can表示客观上的可能， 有时会； may/might/could表示可能； must表示一定； should/ought to表示应该/按说应该 (2)否定句： can’t/couldn’t表示不可能； may not/might not表示可能不； shouldn’t/oughtn’t to表示应该不会 (3)疑问句： can/could表示惊讶、怀疑、不相信的态度 Credit cards provide us with lots of convenience, but they can lead to problems. 信用卡给我们提供了许多方便， 但有时也会带来一些问题。 3．表请求、建议、命令、允许、允诺、禁止、义务、责任 (1)请求对方允许时用May/Can/Could I/we... ? (2)主动提出帮忙或提出建议时用Shall I/we... ? (3)提出请求、问题、看法时用Will/Would you... ? 或Shall he/she/they... ? (4)should/ought to表示应该， shouldn’t/oughtn’t to表示不应该 (5)may/can(可以)表示允许、许可 (6)must(必须), mustn’t表示禁止 (7)shall与第二、三人称连用， 用于陈述句， 表示命令、警告、允诺、威胁； 当宣布法律、规定时也常用shall One of our rules is that every student shall wear school uniform while at school. (规定) 我们其中的一项规定是， 学生在校期间穿校服。 4．表必要性 (1)must do sth. 表示“必须做某事” (2)needn’t/don’t have to表示“不必” You needn’t get the machine repaired this week. I won’t need it until next month. 这周你不必请人修理机器， 到下个月我才用呢。 5．表意愿、决心 will/would可与各种人称连用， 表示主语的意志或决心。 will表示意愿时其否定形式为won’t, 通常用于有生命体， 但有时也用于无生命体， 这时把无生命体拟人化了。 —Why hasn’t the cook arrived yet today? ——为什么今天厨师还没来？ —She just will not come for such a low salary. ——这么低的薪水她不愿意来了。 情态动词的6种特殊用法 1．can/could的否定式与比较级连用表示最高级。 2．can/could的否定式与enough或too (much)连用表示“再……也不为过”。 3．must可表示“偏要， 硬要” , 常用于疑问句或条件状语从句。 4．may/might as well表示“最好； 不妨” 。 5．would可表示过去的习惯， 与used to相比， 前者常表示过去反复的动作， 后者常表示过去的状态或习惯， 现在已不复存在。 6．should有时表示说话人对某事感到意外、惊奇， 意为“竟然会” 。 If you must go, at least wait until the storm is over. 如果你偏要走， 至少等到暴风雨结束。 When we worked in the same firm several years ago, we would often go to the cinema together. 12年前我们在同一个公司上班时， 我们常常一起去看电影。 “情态动词＋have done” 的2类用法 1．对过去发生的事情或状态进行推测 must have done (过去)一定……； 语气比较肯定； 用于肯定句 may (might) have done (过去)可能……； 语气不确定； 用于肯定句和否定句 can (could) have done 用于否定句和疑问句， 表示怀疑或不确定     Since nobody gave him any help, he must have done the research on his own. 既然没有人帮助他， 他一定是独自做的研究。 (浙江高考)I couldn’t have enjoyed myself more—it was a perfect day. 我从没有玩得这么开心过——这真是完美的一天。 2．表示“与过去事实相反” could have done 过去本可以做某事但实际上没做 needn’t have done 过去本不必做某事但实际上做了 ought to/should have done 过去本应该做某事但实际上没做 oughtn’t to/shouldn’t have done 过去不应该做某事但实际上做了 might have done 过去可能做某事但实际上没做     —The taxi driver is to blame for the serious accident. ——出租车司机应为这起严重的事故负责。 —I can’t agree more. He shouldn’t have drunk. ——我非常赞同。 他本不应该喝酒的。 (北京高考)We could have faced the difficulty together, but why didn’t you tell me? 我们本可以共同面对困难， 可你为什么不告诉我呢？ 单句语法填空 1．We can’t imagine that two children ____________ be killed by the washing machine of their house. 答案：should 2．—Who is the man over there? Is it Mr. Li? —No, it ____________ be him. Mr. Li is much taller. 答案：can’t 3．It is required by the rules that students ____________ get grades not lower than 80 in any subject in order to win the scholarship. 答案：shall 4．Growing up ____________ be difficult, for we will come across many things that confuse us. 答案：can 5．—What a slow bus this is! —Yes, we ____________ just as well walk. 答案：may/might 6．Sorry, Cathy, I didn’t know that you were badly short of money then. But you ____________ have asked me for help. 答案：could 7．(2016·北京丰台区期末考试)Judging from his accent, he ____________ not be from Australia. 答案：can 8．(2014·重庆高考单项填空)I’ve ordered some pizza, so we ____________ worry about cooking when we get home tired. 答案：needn’t 虚拟语气用于条件状语从句中的4种情况 1．虚拟语气在if条件句中的运用 类别 从句谓语动词 主句谓语动词 与现在事实相反 过去式(be用were) should/would/could/might＋动词原形 与过去事实相反 had＋过去分词 should/would/could/might＋have＋过去分词 与将来事实相反 过去式(be用were) should/would/could/might＋动词原形 should＋动词原形 were to＋动词原形       (湖南高考)Sorry, I am too busy now. If I had time, I would certainly go for an outing with you. 对不起， 我现在太忙了。 要是有时间， 我一定与你一起去郊游。 2．虚拟条件句中的省略与倒装 如果虚拟条件句中含有were/had/should, 有时可把if省略， 把were/had/should提到主语之前形成倒装； 若为否定形式， not不可提前。 Had he caught the morning train, he would not have been late for the meeting. 要是他赶上了早晨的火车， 那他就不会开会迟到了。 3．错综时间条件句 有时条件句的动作与主句动作发生的时间不一致， 这时动词的形式应根据它们各自表示的时间加以调整。 (北京高考)If we had booked a table earlier, we wouldn’t be standing here in a queue. 如果我们早些订位子， 现在也就不用站在这里排队了。 (if条件句是对过去的虚拟， 而主句是对现在的虚拟)。 4．含蓄条件句 (1)有时假设的情况不用条件句表达， 而是用but for, without等介词(短语)或上下文来表示。 We wouldn’t have finished the project on time without your timely help. 如果没有你的及时帮助， 我们就不能按时完成那项工程了。 (2)用连词otherwise, or等暗示后文与前面的情况相反， 从而引出后文的虚拟语气。 (3)虚拟条件通过but暗示出来， 模式为“虚拟情况＋but＋真实情况” 。 虚拟语气用于名词性从句中的4种条件 1．在“It is＋important/necessary/natural/strange/essential/vital/a pity＋that... ” 句型中， 谓语动词用(should＋)动词原形。 It’s vital that we (should) take our safety driving along the road seriously. 认真对待我们在路上开车时的安全非常重要。 2．在would rather(that)后的宾语从句中， 从句的谓语动词如果表示现在或将来要发生的动作， 从句用一般过去时； 如果表示过去发生的动作， 从句用过去完成时。 I’d rather he had gone to the seaside with me the day before yesterday. 要是他前天和我去海边就好了。 3．句中含有以下单词或变形时， 该句中的名词性从句(宾语从句、表语从句、主语从句、同位语从句)部分常用虚拟语气， 其谓语动词形式为“should＋动词原形”， 其中should可以省略。 一坚持    　insist 二命令  order, command 三建议  suggest, advise, recommend 四要求  request, require, ask, demand 外加一个敦促  urge Teachers recommend parents not allow their children under 12 to ride bicycles to school for safety. 老师建议父母出于安全考虑最好不要让12岁以下的孩子骑自行车去学校。 4．wish后宾语从句中的虚拟语气 虚拟语气 从句谓语动词 与现在事实相反 过去式(be动词一般用were) 与过去事实相反 had＋过去分词 与将来事实相反 would/could＋动词原形     We wish that we had visited the Great Wall last year. 我们要是去年去参观长城就好了。 3个特定句式中的虚拟语气 句型结构 过去虚拟 现在虚拟 将来虚拟 if only引导的条件句及感叹句 had＋过去分词 过去式(be动词一般用were) would/could/should/might＋动词原形 as if/though引导的表语从句及方式状语从句 had＋过去分词 过去式(be动词一般用were) would/could/should/might＋动词原形 It is (high) time (that)... 过去式或“should＋动词原形”         What a terrible accident! If only the driver hadn’t driven so fast then! 多么可怕的事故！ 要是司机当时开车没那么快就好了。 单句语法填空 1．(2015·北京高考单项填空)If I ____________ (not see) it with my own eyes, I wouldn’t have believed it. 答案：hadn’t seen 2．(2014·福建高考单项填空)If there ____________ (be) no modern telecommunications, we would have to wait for weeks to get news from around the world. 答案：were 3．(2015·江苏高考单项填空)Many of the things we now benefit from ____________ (not be) around but for Thomas Edison. 答案：would not be 4．(2015·安徽高考单项填空)It is lucky we booked a room, or we ____________ (have) nowhere to stay now. 答案：would have 5．(2015·重庆高考单项填空)Without his wartime experiences, Hemingway ____________ (not write) his famous novel A Farewell to Arms. 答案：wouldn’t have written 6．(2015·陕西高考语法和词汇知识)Ellen is a fantastic dancer. I wish I ____________ (dance) as well as her. 答案：danced 7．(2016·陕西长安一中质检)The villagers are extremely thankful to him, without whose help the road to the village ____________ (build)． 答案：couldn’t have been built 8．(2016·福建清流一中期中考试)I saw her in the office this morning.She ____________(come) back to work without the doctor’s permission. 答案：shouldn’t have come 9．If only we ____________(have) the opportunity to work in Tibet next year. 答案：could have 10．(2016·湖南怀化质检)Had it not been for my teacher’s help, I ____________(not win)the first place in the contest. 答案：wouldn’t have won 单句语法填空 1．(2015·全国卷样题语法填空)Are they there? Oh, my goodness. I ____________ have put them there when the phone rang. 答案：must 2．(2015·北京高考单项填空)—Can’t you stay a little longer? —It’s getting late. I really ____________ go now. My daughter is home alone. 答案：must 3．(2015·陕西高考语法和词汇知识)You ____________ feel all the training a waste of time, but I’m a hundred percent sure later you’ll be grateful you did it. 答案：may/might 4．(2015·天津高考单项填空)I ____________ (not worry) before I came to the new school, for my classmates here are very friendly to me.