2019届高三英语二轮复习课件：第一部分语法专题第六节情态动词和虚拟语气(共65张PPT) 65页

第六节　情态动词和虚拟语气 情态动词 　 考点一　情态动词的基本用法 1. can 和 could 的用法 (1) 表示 “ 能力 ” ，意为 “ 能，会 ” 。 ◆ ( 2017· 北京卷 ) Samuel, the tallest boy in our class ， can easily reach the books on the top shelf. Samuel 是我们班最高的男孩，他能轻易地够着书架顶层的书。 ◆ ( 浙江卷 )It was so noisy that we couldn't hear ourselves speak. 这里如此嘈杂以至于我们无法听到自己说话。 (2) 表示理论上的可能性，意为 “ 有时候可能会 ” ，用于肯定句。 ◆ ( 2018· 北京卷 )In today's information age, the loss of data can cause serious problems for a company. 在今天的信息时代，数据的丢失有时会对一个公司造成严重的问题。 (3) 表示礼貌地请求，意为 “ 能，可以 ” 。在疑问句中 could 可代替 can, 语气更委婉。 ◆ ( 2016· 江苏卷 )—Can you tell us your recipe for happiness and a long life? —— 你能告诉我们你的幸福和长寿的秘诀吗？ — Living every day to the full, definitely. — — 过好每一天。 (4) 用于固定句式中： cannot... too/enough “ 无论 …… 也不过分 ” ； “ 越 …… 越好 ……” 。 ◆ ( 陕西卷 )I can't thank you too much for all your help to my son while we were away from home. 我非常感谢你，在我们不在家时帮助我的儿子。 2. may 和 might 的用法 (1) 表示许可和请求，在疑问句中 might 比 may 的语气更委婉。 ◆ ( 北京卷 )Might/May I have a word with you? It won't take long. 我可以和你说句话吗？不会耽误很长时间。 (2) 表示推测，意为 “ 可能，或许 ” ，通常不用于疑问句中。 ◆ ( 北京卷 )—You needn't take an umbrella. It isn't going to rain. —— 你不必带伞。不会下雨的。 — Well, I don't know. It might do. —— 嗯，我不知道，可能会下吧。 (3) 用于固定句式： may as well ＋动词原形 “ 最好；倒不如 ……” 。 ◆ Since it is raining hard, you may as well stay here. 既然雨下得这么大，你倒不如待在这儿。 3. must 的用法 (1) 表示义务、必要性等，意为 “ 必须 ” 。其否定式 mustn't 意为 “ 禁止 ” 。 ◆ ( 湖北卷 )We must act quickly as possible now. Just tell us whether you can undertake the task or not. 现在我们必须尽快采取行动。你就告诉我们你能否承担这项任务。 (2) 表示偏执，固执，意为 “ 非得，偏要 ” 。 ◆ ( 辽宁卷 )If you must go, at least wait until the storm is over. 如果你非要走，至少要等到暴风雨停了。 4. shall 的用法 (1) 用于第一、第三人称疑问句中，表示说话人征求对方的意见或向对方请示。 ◆ Henry is waiting outside. Shall he come in, sir? 亨利正在门外等着，要他进来吗？ (2) 用于第二、第三人称陈述句中，表示说话人给对方的命令、警告、允诺或威胁。 ◆ ( 辽宁卷 )One of our rules is that every student shall wear school uniform while at school. 我们有一条规定，那就是每名学生在校期间都必须穿校服。 5. should 的用法 (1) 表示劝告和建议，意为 “ 应该 ” 。 ◆ I don't think you should give up the opportunity to go to university which you have been dreaming about. 我认为你不应该放弃你一直以来梦想的上大学的机会。 (2) 表示推测、可能性或预期，意为 “ 应该；可能 ” 。 ◆ ( 朗文辞典 )Try phoning Robert—he should be home by now. 给罗伯特打个电话试试，他现在应该到家了。 (3) 用于表示感情或意志等的 that 从句中，意为 “ 竟然 …… ；居然 ……” 。 ◆ ( 江苏卷 )It was sad to me that they, so poor themselves ， should bring me food. 让我难过的是，如此贫穷的他们竟然给我带来了食物。 6. will 和 would 的用法 (1) 表示意志或意愿。 will 指现在， would 指过去。 ◆ I have told him again and again to stop smoking, but he will not listen. 我已再三告诉他戒烟，但是他就是不听。 ◆ ( 江苏卷 )Days later, my brother called to say he was all right, but wouldn't say where he was. 几天后，我哥哥打电话说他一切都好，但不愿意说他在哪儿。 (2) 表示习惯性动作，意为 “ 总是 ” ， will 指现在， would 指过去。 ◆ ( 四川卷 )I still remember my happy childhood when my mother would take me to Disneyland at weekends. 我仍旧记得快乐的童年，那时我妈妈经常在周末带我去迪斯尼乐园。 (3) 表示征求意见或提出请求，多用于第二人称疑问句中。 would 比 will 语气委婉。 ◆ Will/Would you please let me have a look at your new watch? 请让我看看你的新表好吗？ 7 ． need 的用法 need 表示必要性，常用于疑问句和否定句中， needn't 表示 “ 不必 ” 。 need 作实义动词时，可用于肯定句、否定句和疑问句中，有人称、数和时态的变化；其后可接名词、代词、带 to 的不定式或动名词作宾语。 ◆ ( 2017· 天津卷 )My room is a mess, but I needn't clean it before I go out tonight. I can do it in the morning. 我的房间里乱糟糟的，不过我今天晚上出门之前没必要打扫，我可以上午再打扫。 8 ． dare 的用法 dare 意为 “ 敢，敢于 ” ，没有人称、数和时态的变化，主要用于疑问句、否定句和条件句中，后接动词原形。作实义动词时，在肯定句中通常接带 to 的不定式，在疑问句和否定句中， dare 之后的不定式可省略。 ◆ How dare you leave your home without your parents' permission? 在没有征得你父母的同意的情况下你怎么敢离开家？ 　 [ 对点演练 ] —— 单句语法填空 / 单句改错 1 ． (2016· 天津卷 ) It was really annoying ； I _______ not get access to the data bank you had recommended. 2 ． ( 重庆卷 )You ______ be Carol. You haven't changed a bit after all these years. 3 ． ( 湖南卷 )—I've prepared all kinds of food for the picnic. — Do you mean we needn't brought anything with us? ________________ could must brought → bring 考点二　情态动词＋ have done 对过去的推测 must have done 一定做过某事 ( 肯定句 ) can/could have done 过去不可能做过 …… ( 否定句 ) 过去可能做过 …… 吗？ ( 疑问句 ) may/might have done 过去可能做过 …… ( 肯定句 ) 过去可能没有做过 …… ( 否定句 ) 对过去情况的后悔、遗憾或责备 could have done 本来能够做但却未做 ( 肯定句 ) should have done 本来应该做但是实际上未做 shouldn't have done 本来不应该做而实际上做了 needn't have done 没必要做却做了 　　 ◆ ( 2016· 浙江卷 )George can't have gone too far. His coffee is still warm. 乔治不可能走得太远。因为他的咖啡还是热的呢。 ◆ ( 陕西卷 )The children must have got lost in the woods; otherwise, they would have been at the lakeside camp as scheduled. 孩子们一定在森林里迷路了；否则，他们会按照计划在湖边露营。 ◆ ( 福建卷 )—Sorry, Mum ！ I failed the job interview again. —— 对不起，妈妈！我工作面试又失败了。 — Oh, it's too bad. You should have made full preparations. —— 哦，太糟糕了。你本应该做好充足的准备。 [ 对点演练 ] —— 单句语法填空 / 单句改错 1 ． ( 天津卷 )I ________ have worried before I came to the new school, for my classmates here are very friendly to me. 2 ． ( 2018· 江苏启东中学月考 )We ______ have faced the difficulty together, but why didn't you tell me? 3 ． ( 陕西卷 )My book ， The House of Hades ， is missing. Who must have taken it? ________________ needn't could must → could/can 虚拟语气 考点一　 if 条件句中的虚拟语气 虚拟语气 主句谓语动词 从句谓语动词 虚拟现在 should/would/could/might ＋ do 过去式 (be 用 were) 虚拟过去 should/would/could/might ＋ have done had ＋过去分词 虚拟将来 should/would/could/might ＋ do 过去式 /were to do/should ＋ do ◆ ( 2018· 北京卷 )They might have found a better hotel if they had driven a few more kilometers. 如果他们多开几公里的话，他们也许会找到一个更好的旅馆。 ◆ ( 北京卷 )We would be back in the hotel now if you didn't lose the map. 如果你没有把地图丢了的话，我们现在就回到旅馆了。 ◆ ( 安徽卷 )Grace doesn't want to move to New York because she thinks if she were to live there, she wouldn't be able to see her parents very often. 格蕾丝不想搬到纽约，因为她认为如果住在那里，她就不能经常看到她的父母了。 [ 对点演练 ] —— 单句语法填空 1 ． (2018· 天津卷 )If we __________(catch) the flight yesterday, we would be enjoying our holiday on the beach. 2 ． ( 2018· 天津十二区县联考 )If he had spent more time practising speaking English before, he __________(be) able to speak it better now. 3 ． ( 2018· 江苏 97 校联考 )—Why didn't you call me then? — Oh, my cell - phone was power off. I _________________(call) you otherwise. had caught would be would have called 考点二　含蓄条件句的虚拟语气 有时假设的条件不通过条件状语从句表达出来，而是隐含在某些词或短语中，或隐含在上下文中，这叫含蓄虚拟语气。常用的这类词或短语有： without( 要是 ) 没有； but for 要不是； otherwise/or 否则等。 ◆ ( 2017· 天津卷 )—Do you have Betty's phone number? —— 你有贝蒂的电话号码吗？ — Yes.Otherwise ， I wouldn't have been able to reach her yesterday. —— 是的，不然我昨天就不可能联系上她了。 ◆ ( 江苏卷 )Many of the things we now benefit from would not be around but for Thomas Edison. 要不是托马斯 · 爱迪生，我们现在从中获益的很多东西就不会存在。 [ 对点演练 ] —— 单句语法填空 / 单句改错 1 ． ( 安徽卷 )It is lucky we booked a room, or we ___________(have) nowhere to stay now. would have 2 ． ( 江西卷 )We _____________(put) John's name on the race list yesterday but for his recent injury. 3 ． ( 福建卷 )We lost our way in that small village, otherwise we will have visited more places of interest yesterday. _____________ would have put will → would 考点三　虚拟语气在从句中的运用 一、 在名词性从句中的运用 1 ．在表示要求、命令、建议、请求等动词后接宾语从句中，以及这些动词的名词后接同位语或表语从句中的谓语动词用 “ (should ＋ ) 动词原形 ” 。常见的此类动词：一坚持 (insist) 、二命令 (order ， command) 、三要求 (require, demand ， request) 、四建议 (suggest ， advise ， propose ， recommend) 。 ◆ ( 江苏卷 )She suggested that Dale join the debating team ， believing that practice in speaking could give him the confidence and recognition that he needed. 她建议戴尔参加辩论队，她认为辩论队里的演讲练习会给予他所需要的信心和认可。 ◆ ( 湖北卷 )He insisted that the problem (should) be discussed at the meeting. 他执意要求在会上讨论这个问题。 ◆ My suggestion was that necessary measures (should)be taken to protect the children from dangerous situations. 我的建议是采取必要措施来保护孩子远离危险的境遇。 2 ．在 “ It is/was ＋ adj ./done ＋ that... ” 句型中，从句中的谓语动词用 (should) ＋动词原形。常见的形容词或过去分词有： important, necessary, strange, suggested, ordered, advised, requested, demanded 等。 ◆ It is necessary that we (should) clean the room every day. 我们每天打扫房间是有必要的。 ◆ It is required that middle school students (should) take at least one hour exercise every day. 中学生被要求每天至少进行一个小时的锻炼。 3 ． wish 后的宾语从句中的谓语可用一般过去时， had ＋过去分词和 could/might/would ＋动词原形，分别表示与现在、过去和将来情况相反。 ◆ ( 天津卷 )I wish I had been at my sister's wedding last Tuesday, but I was on a business trip in New York then. 我多么希望上周二参加了我妹妹的婚礼，但是当时我在纽约出差。 ◆ ( 陕西卷 )Ellen is a fantastic dancer. I wish I danced as well as her. 埃伦是一个极出色的舞者。我希望能够跳得和她一样好。 ◆ I wish you could give me the book you borrowed from me last week tomorrow. 我希望你明天把你上周从我这儿借的书还给我。 4 ． would rather 所接的宾语从句中，从句的谓语如果表示现在或将来要发生的动作，从句用一般过去时；如果表示过去发生过的动作，从句用过去完成时。 ◆ ( 陕西卷 )We would rather our daughter stayed at home with us, but it is her choice, and she is not a child any longer. 我们宁愿女儿待在家，陪在我们身边，但是选择权在她手上，毕竟她不再是个孩子了。 二、三个固定句式中的虚拟语气 句式 现在虚拟 过去虚拟 将来虚拟 if only 引导的条件句及感叹句 过去式 had ＋过去分词 would/could/might ＋动词原形 as if/though 引导的表语从句及方式状语从句 过去式 had ＋过去分词 would/could/might ＋动词原形 It is (high) time that... 过去式或 should ＋动词原形 ◆ ( 重庆卷 )It was John who broke the window. Why are you talking to me as if I had done it? 打破窗户的是约翰。为什么你说得好像是我打破的似的？ ◆ It is high time that we took/should take some measures to solve the problem. 确实到了我们采取措施解决问题的时候了。 ◆ Look at the trouble we are in.If only we had taken our teacher's advice! 看看我们所处的困境，要是我们当初听从老师的建议该多好！ [ 对点演练 ] —— 单句语法填空 / 单句改错 1 ． ( 2018· 山西太原外国语月考 )Though his face suggested that there _____(be) nothing serious, the doctor still suggested he ____________(stay) in bed for a few days. was (should) stay 2 ． ( 2018· 江苏运河中学诊断 )If only he ________(lie) quietly as instructed, he would not suffer so much now. 3 ． It is high time that we ____________________(devote) ourselves to environmental protection and ecological improvement. 4 ． ( 2018· 山东曲阜师大附中模拟 )I believe we'll turn our school into a better place. How I wish we can enjoy a better school life. _____________ 5 ． They met for the first time, but they talked happily as if they have been good friends for a long time. __________ had lain should devote/devoted can → could have → had Ⅰ . 单句语法填空 1 ． ( 2018· 包头市模拟 )As Father and Mother thought it was a big occasion for me, they suggested I________(hold) a birthday party at home to celebrate it. 【 解析 】 考查虚拟语气。 suggest 表示 “ 建议 ” 时后面宾语从句的谓语动词应用 (should) ＋动词原形，故填 (should) hold 。 【 答案 】 (should) hold 2 ． ( 2018· 重庆市第一次质量抽测 )If the new safety system________(bring) into use, the accident would never have happened. 【 解析 】 句意：如果新的安全系统已经投入使用，事故就不会发生了。根据句意、句子结构以及主句中的 would never have happened 可知，句中 If 引导的是虚拟条件句，且表示与过去的事实相反的假设，故从句时态应用过去完成时。 【 答案 】 had been brought 3 ． ( 2018· 北京朝阳区期中统考 )If we________(take) another road, we wouldn't have been stuck in the traffic jam for so long. 【 解析 】 考查虚拟语气。句意：如果我们走了另一条路，我们就不会在交通堵塞中被困这么久。此处是对过去情况的假设，所以从句谓语用 had done 形式。 【 答案 】 had taken 4.( 2018· 湖南长沙四校模拟 )—I________thank you enough for what you have done for me. — You're welcome. 【 解析 】 句意： —— 你为我做的一切我无论怎么感谢都不为过。 —— 不用谢。 can not...enough 表示 “ 再 …… 也不为过 ” 。 【 答案 】 can't 5 ． ( 2018· 安徽江淮十校联考 )As the deadline is drawing near, no one________leave with his own work uncompleted. 【 解析 】 句意：因为截止日期即将到来，不完成工作，任何人不许离开。 shall 用于第三人称陈述句中，表示命令、警告，符合句意。 【 答案 】 shall 6 ． ( 2018· 湖北四地七校联考 )It is high time that you________(consider) that if there were no stress in your life, you would achieve a little. 【 解析 】 在 It is high time that... 句式中，从句用虚拟语气，即：谓语动词用过去式或 should ＋动词原形。 【 答案 】 considered/should consider 7 ． ( 2018· 广东实验中学月考 )—Why are your eyes so red? You________have slept well last night. — Yeah, I stayed up late writing a report. 【 解析 】 句意： —— 你的眼为什么这么红？你昨晚一定睡得不好。 —— 是的，我熬夜写报告了。此处表示对过去的否定情况把握比较大的推测，故用 can't have done 不可能做了某事。 【 答案 】 can't 8 ． ( 2018· 江西师大附中等五校联考 )It has been accepted that all the students________put on masks before going to school in case they are infected with flu virus. 【 解析 】 在第三人称作主语的陈述句中，表示规定、制度，应用 shall 。 【 答案 】 shall 9 ． ( 2018· 浙江杭州地区七校模拟 )When you phoned me, I was having a meeting; how I wish I________(answer) your call. 【 解析 】 句意：当你给我打电话的时候，我正在开会。我多么希望我 ( 之前 ) 接了你的电话。 wish 后的从句中用虚拟语气，根据句意可知是对过去情况的虚拟，所以谓语动词用 had done 形式。 【 答案 】 had answered 10 ． ( 2018· 广东惠州高三二调 ) Harry is feeling uncomfortable. He________have drunk too much at the party last night. 【 解析 】 句意： Harry 觉得不舒服，他昨晚在聚会上肯定喝太多了。由 last night 及语境可知，此处表示对过去的肯定情况把握较大的推测。 must have done sth. “ 一定做了某事 ” 。 【 答案 】 must 11 ． ( 2018· 西安工大附中第四次训练 )I should not have laughed if I________(think) you were serious. 【 解析 】 句意：如果我 ( 当时 ) 认为你是认真的，我就不会笑了。主句中谓语动词使用 should not have laughed ，表明与过去的事实相反，从句谓语动词应该使用 had done 形式。 【 答案 】 had thought 12 ． ( 2018· 山东高三模拟 )She is a quiet girl at school, but sometimes she________be very naughty. 【 解析 】 语境表示她有时候会很顽皮，此处应用 can 表示对某人一时的特征，意为 “ 有时会 ” 。 【 答案 】 can 13 ． ( 2018· 东北三校联考 )The order came that the medical supplies________(send) to the earthquake - stricken area soon. 【 解析 】 表示建议、要求、命令等的名词 suggestion ， order ， request ， advice 等的表语从句、同位语从句中谓语动词用 (should ＋ ) 动词原形。 【 答案 】 (should) be sent 14 ． ( 2018· 陕西渭南一模 )It is required by law that a driving test________(take)before a man gets a license. 【 解析 】 句意：法律规定，一个人在获得驾照之前要先参加驾照考试。 It is required that... 中， that 从句的谓语动词用 “ should ＋动词原形 ” ，其中 should 可以省略；又因为 test 与 take 之间是被动关系，故用被动语态，即 (should)be taken 。 【 答案 】 (should)be taken 15 ． ( 2018· 天津七校 4 月联考 )I was ill that day ， otherwise I ________(take) part in the sports meet. 【 解析 】 句意：那天我病了，否则我就参加运动会了。根据语境可推知，设空处为与过去事实相反的虚拟语气，故答案为 would have taken 。 【 答案 】 would have taken 16.( 2018· 江苏苏州调研 )John wants to see me now, but I have so much work on hand that I would rather he__________(come) tomorrow than today. 【 解析 】 句意：约翰现在想看我，但是我手头有很多工作要做，我宁愿他明天来不是今天。 would rather 后面接从句，用虚拟语气，和现在和将来相反用一般过去式，和过去相反用过去完成时，选 came 。 【 答案 】 came 17 ． ( 2018· 江苏南京二模 )He was greatly shocked at the man's taking office. Never did he expect that the voters________be so unreasonable. 【 解析 】 句意：他对那个人的就职大为震惊。他从未料到选民竟然如此不理智。根据前面的 greatly shocked 可知，他感到出乎意料，故填 should ，表示惊讶和意外，意为 “ 竟然 ” 。 【 答案 】 should 18 ． ( 2018· 湖南十三校第一次联考 )I________thank you too much because without your help I wouldn't have won the first prize. 【 解析 】 句意：我再谢也不为过，因为没有你的帮助，我不可能获得一等奖。 can't...too much 表示 “ 再 …… 也不为过 ” 。 【 答案 】 can't 19 ． ( 2018· 山西省省级名校联考 ) This printer is of good quality. If it__________(break) down within the first year, we would repair it at our expense. 【 解析 】 考查虚拟语气用法。前句表示打印机质量好，按道理第一年内不可能出故障，所以下句提出了一种将来的可能性不大的假设，由此判断为与将来事实相反的假设。 【 答案 】 should break/were to break/ broke 20 ． ( 2018· 湖北七市教科研协作体联考 )I________(go)to my cousin's birthday party last night, but I was not available. 【 解析 】 句意：要不是昨晚抽不出时间，我就去参加我堂弟的生日聚会了。结合句意和句中的 but I was not available 可知，题干前半句为含蓄条件句；由 last night 可知，该含蓄条件句表示对过去情况的虚拟，故谓语形式为 would/should/could ＋ have done 。 【 答案 】 would/could/might have gone Ⅱ . 单句改错 1 ． ( 2018· 安徽合肥期中 ) When I got the papers, I realized that things would be better if I listened to the teacher attentively. __________ 【 解析 】 根据语境和主句中的谓语 realized 可知， if 引导的条件状语从句所叙述的事情与过去的事实相反，应用虚拟语气，故 if 条件状语从句的谓语动词应用过去完成时。 【 答案 】 listened 前加 had 2 ． ( 2018· 石家庄市一模 )Whenever I made mistakes and felt discouraged, my teacher and my classmates would help me figure out how I must have avoided them. __________ 【 解析 】 根据语境可知，该句表示 “ 过去本能够做但却未做 ” ，故用 could have done 。 【 答案 】 must → could 3 ． ( 2018· 成都经开区实验高级中学模拟 )Therefore, we strongly suggested that similar events held more and more in the future! __________ 【 解析 】 suggest 在此处表示 “ 建议 ” ，后跟宾语从句时用虚拟语气，谓语动词为 “ (should) ＋动词原形 ” ，其被动语态为 (should) be done 。 【 答案 】 held 前加 be 4 ． ( 2018· 成都市模拟 )In my opinion, by doing part - time jobs, college students must gain some social experience and broaden their outlooks. __________ 【 解析 】 根据语境可知，此处表示通过做业余工作能够获得社会经验，而不是一定获得。 【 答案 】 must → can 5 ． ( 2018· 银川一中二模 )I suggest that our school must take measures to encourage more students to take part in sports. __________ 【 解析 】 suggest 在此处表示 “ 建议 ” ，后跟宾语从句时用虚拟语气，谓语动词为 “ (should) ＋动词原形 ” ， should 可省略。 【 答案 】 must → should 或去掉 must 6 ． ( 2018· 云南省 11 校跨区调研考试 )A real eco - travel should like this: take nothing away but your good memory; leave nothing behind but all clean water and green trees. __________ 【 解析 】 此处 like this 为介词短语作表语，前面少了系动词 be 。 【 答案 】 should 后加 be 7. (2018· 四川成都摸底考试 )I believe everyone must have a bright future, as long as he or she makes an effort, taking an optimistic view of life. __________ 【 解析 】 根据句中的 as long as he or she...life( 只要他或她努力，对生活持乐观的态度 ) 可知，此处指 “ 我相信每个人都会有一个美好的未来 ” ， believe 后的宾语从句应表示 “ 有可能；会 ” ，从句中可用情态动词 can 或 will 。 must 表示 “ 必须 ” ，不符合语境。 【 答案 】 must → can/will 8 ． ( 2018· 南昌十校二模 )As a result ， I suggest we are given less homework and more time for out - of - classroom activities. Only in this way can we live a happy and healthy life. __________ 【 解析 】 虚拟语气错误。 suggest 在此处表示 “ 建议 ” ，因此后跟的宾语从句应用虚拟语气，即从句谓语用 “ should ＋ do ” 形式，且 should 可以省略。故此处应把 are 改为 be 。 【 答案 】 are → be 9 ． ( 2018· 河北邯郸联考 )When you walk into the gallery, you feel as if you are inside a fragile, white seashell. __________ 【 解析 】 as if 后接表语从句， 根据句意 “ 你感觉自己像是身处于一枚易碎的白色贝壳之内 ” 可知，此处是对现在事实的虚拟，从句应用一般过去时。 【 答案 】 are → were 10 ． ( 2018· 山东曲阜模拟 )We needn't to do so much homework. Therefore, we have more time for after - school activities. __________ 【 解析 】 need 可作实义动词，有时态和数的变化；也可作情态动词，后接动词原形。根据 needn't 可知， need 在此为情态动词，后接动词原形。 【 答案 】 去掉 to