英语助动词语法2讲.doc

昂立英语 第一讲 助动词英语的助动词可大致分为三类：基本助动词do、be、have；情态助动词can、could、may、might、will、would、shall、should、ought to、need、dare等；半助动词be going to、be able to、have to、used to、happen to、seem to等。一、can、could、may、might、must（一）can的用法 （1）表示“能力”l He cant drive a car. 他不会开车。（2）表示“许可”l Can I go home now? 我现在可以回家了吗？（3）表示“可能”通常用于否定句和疑问句。例如：l Weve got a map. We cant lose our way. 我们有地图，不可能迷路的。（二）could的用法（1）表示“能力”Could是can的过去时形式，但只有在过去时间的语境中，could才表示过去的能力。例如：l When we were at school, I couldnt speak English as well as my brother.（2）表示“许可”只有在过去时间的语境中，could才表示过去的许可。例如：l She asked if she could get another drink.但若不是出现在过去时的语境中，could和can的用法一样，但语气更客气。例如：l I wonder if I could leave the car in the road.（3）表示“可能”只有在过去时间的语境中，could才表示过去的可能。例如：l When he was younger, he could be popular with girls.但若不是出现在过去时的语境中，could和can的用法一样，但语气更客气。例如：l This could be a big chance of yours.（三）may的用法（1）表示“许可”l You may go home now.l May I ask you a question?表示“许可”，may在口气上比can要严肃些。（2）表示“可能”l You may be right. 你可能是正确的。注意，表示“可能”，may用于肯定句，can用于否定句和疑问句。试比较：l He may be serious.l He cant be serious.（四）might的用法（1）表示“许可”might是may的过去时形式，但只有在过去时间的语境中，might才表示过去的“许可”。例如：l She asked if she might go home then.但若不是出现在过去时的语境中，might仅表示一种委婉语气。例如：l We might ask Tom to chair the meeting. （试探性建议）（2）表示“可能”在过去时间的语境中，might表示过去的“可能”。例如：l He said he might be working late that night.但若不是出现在过去时的语境中，might仅表示一种委婉语气。例如：l You might be a little more careful in future. （轻微的谴责）（五）must的用法（1）表示“义务”l He must do as he is told.must not表示“不许”，即表示“禁止”。例如：l You must not touch this.（2）表示“推测”l There must be something wrong with the machine.l You must be joking.要注意，must表示“推测”的否定形式不能用must not，而要用cannot或cant。试比较：l A: He must be in his eighties.B: He cant be so old.二、will、would（一）will的用法（1）表示“预见”Will表示“预见”的用法就是一种将来时间的表达法。例如：l We will arrive after dark.l On June 10th, my parents will have been married for 50 years.（2）表示“意愿”l Will you give me a hand, please?l I will do my best.（3）表示“意图”l We will never do it again.（4）表示“推测”l They will be home at this time of day.（5）表示“习惯性动作”l Water will boil at 100.will的这个用法可用一般现在时代替。例如：l Water boils at 100.（二）would的用法would是will的过去时形式。例如：l She told me John would be fifty next month. （表示“预见”，即过去将来）l He asked if someone would open the window. （表示过去的“意愿”）但若不是出现在过去时的语境中，would仅表示一种委婉语气。例如：l Would you call back in an hour? （客气的请求）I was given a toy yesterday.A toy was given to me yesterday.（5）当主动句是一个“主动宾补”结构时，可将原来的宾语变为被动句的主语，原来的宾语补语变为被动句里的主语补语。例如：They named the boy Tom.The boy was named Tom.We painted the wall pink.The wall was painted pink. 三、某些不用被动态的用法在英语里，有些表达只能用主动态。例如：The door wont lock. 门锁不上。The cloth washes well. 这布料很耐洗。The drawer wont open. 这抽屉打不开。His novel sells well. 他的小说销路很好。This paper tears easily. 这纸一撕就破。第二讲 助动词一、shall、should（一）shall的用法shall用于第一人称主语可表示“预见”，但仅限于较拘谨的英国英语。例如：l I shall leave for Australia next Tuesday.（二）should的用法should是shall的过去时，但在当代英语中，两者在语义上已没有多少联系了。（1）表示“义务”l You should hand in your essays next Monday.（2）表示“推测”l The plane should be landing now.二、ought to、used to、need、dare（一）ought to的用法ought to的意义和用法同should相似，常常交替使用。（1）表示“义务”l I ought to drive slowly here.在疑问句和否定句中，通常用should。（2）表示“推测”l Harry ought to be at his office.（二）used to的用法used to只有过去时形式。（1）表示过去的状态l There used to be a high school here. （现在已不复存在）l She used to be a doctor, but now she is doing business.（2）表示过去的习惯动作l I used to go to work by bus, but nowadays I take a bike.used to在疑问句和否定句中并不常见，通常这么用：l Did you use to go to work by bus?l I didnt use to go to work by bus.在附加疑问句中，通常用didnt形式：l He used to smoke a lot, didnt he?（三）need的用法need既可作主动词，也可作情态助动词。作为情态助动词，need通常用于否定句和疑问句，表示“必要”。例如：l A: Must you go?B: Yes, I must.B: No, I neednt.又如：l A: Need he finish his work today?B: Yes, he must.B: No, he neednt.need作主动词必须下接动词不定式。例如：l I need to know.l You dont need to go.（四）dare的用法dare既可作主动词，也可作情态助动词。作为情态助动词，dare通常用于否定句、疑问句和感叹句。例如：l The government dare not increase the tax on food.l How dare you say that!三、半助动词英语中有一些兼有主动词和助动词特征的语法结构，叫做“半助动词”。我们以have to为例，来观察半助动词的两重性：l I must go now.l I have to go now.在这里，have to可以代替must，起情态助动词的作用。然而，have to之前还可以用其它助动词，这是一般的情态助动词所没有的用法。例如：l You dont have to go to school today.l You will have to finish your work by the weekend.最常见的半助动词有以下两类：（一）以be开头的半助动词这类半助动词包括be going to、be able to、be about to、be able to、be certain to、be sure to、be likely to等。例如：l I wont be able to come, Im afraid.l Look out! The train is about to move.l They are likely to win the game.（二）以have/had开头的半助动词这类半助动词包括have (got)