【正文】 “需要”， I att。(客觀條件必須現(xiàn)在走)You must be here on time next 。You must do it 。clock already, we must have been late ，我們一定又遲到了。It39。He must have told my parents about 。He had to go because of somebody?s calling him that ，因為有人叫他。Must I return the book tomorrow? 我必須明天還書嗎?After such a long walk, you must be , 你一定累了。You mustn39。must 用來指一般現(xiàn)在時和一般將來時，過去式可用 have to 的過去式代替。Might I borrow some money now? 我可以借點錢嗎? He might be 。might 是may 的過去式，有兩種用法，一種表示過去式，一種表示虛擬語氣，使語氣更加委婉、客氣或?qū)赡苄缘膽岩?。He said he might lend us some 。You may take the book 。With the teacher?s help, I shall be able to speak English , 我將能準(zhǔn)確地講英語。Can you pass me the books? 你能給我遞一下書嗎 ? Could you help me, please? 請問, 你能幫助我嗎? What can you do? 你能干點什么呢? Can you be sure? 你有把握嗎?can 和could 只能用于現(xiàn)在式和過去式兩種時態(tài)，將來時態(tài)用be able to 來表示。t help ，我?guī)筒簧夏?。I39。We can39。個別情態(tài)動詞有現(xiàn)在式和過去式兩種形式，過去式可以用來表達更加客氣、委婉的語氣，時態(tài)性不強，可用于過去，現(xiàn)在或?qū)?。He must have been 。情態(tài)動詞數(shù)量不多，但用途廣泛，主要有下列： can(could), may(might), must, need, ought to, dare(dared), shall(should), will(would).二、情態(tài)動詞的位置情態(tài)動詞在句中放在謂語動詞之前，謂語動詞前若有助動詞，則在助動詞之前，疑問句中，情態(tài)動詞放在主語之前。We can be there on time 。t see you in class must have been ，你肯定沒有來。It must have rained last night for it is so wet ，昨晚肯定下雨了。It must be that naughty boy crying 。對現(xiàn)在或未來的事進行猜測時，后接動詞原形；對已經(jīng)發(fā)生的事進行猜測時，后接have + 過去分詞。t do me any ，我不會擔(dān)心那件事的，因為它不會給我?guī)硎裁春锰帯ell, I wouldn39。I will make this puter work even if I have to stay up all 。The person you mentioned would be the father , is that right ? 你說的那個人一定是爸爸了，對嗎？That would be in 1999 , I 。re looking 。He would sit there for hours, doing nothing at ，什么都不干。3）表示習(xí)慣、傾向（可譯成“總是會、老是，等”）Sometimes the cat will lie there all ，那只貓總是整個下午都躺在那兒。t let the doctor take his blood 。I will pay you at the rate you 。ll be back in twenty minutes ? 請告訴她我二十分鐘后回來，好嗎？If you want help, just let me know , will you ? 你需要幫助就告訴我，好嗎？Won39。當(dāng)然will 和would又都有一些各自不同的獨特用法。）I was shocked that she should have said such a thing to you.（她竟然對你說這種話，真讓我吃驚。Take an umbrella with you in case it should ，以防萬一下雨。I39。s care the girl should not be speaking to you ，這個女孩現(xiàn)在就不能與你說話了。4）用于某些從句中表示虛擬語氣The doctor insisted that the girl should be 。It39。3）表示驚訝、失望等情緒I think it is dreadful that anyone should be so ，竟然每個人都如此傷心就太糟糕了。The event should lead them to a even worse economic 。t be out in such an early 。They should do it for their own 。You should write to your parents at least once a 。）1）表示出于職責(zé)、義務(wù)該做某事You shouldn39。should（用作情態(tài)動詞時，有時表示具體的意思，有時卻沒有意義。The renter shall keep the house in a neat and orderly 。This law shall e into effect on January 1st 2001 這個法律于2001年元月1日生效。3）決心（表示某事一定會發(fā)生）That day shall 。He shall not e into my 。2）命令You shall e to my office 。t be ，她不會太受壓的。t want to be hard on your daughter。“Whatever you want you shall have , ”said the ：“你想得到什么，你就可以有什么。Every time she was in trouble, she would go to him for 用作情態(tài)動詞時,適用于第二人稱和第三人稱。竟然They should be home by 、will的基本用法(1)表意愿，用于各人稱陳述句，可以表示“意志”或“決心”，如：I have told him again and again to stop smoking, but he will not you will read the book, I will lend it to you.(2)在疑問句中用于第二人稱，表示說話人向?qū)Ψ教岢稣埱蠡蛟儐枌Ψ降囊庠?，如：Will you please tell me how to get to the Capital Gymnasium?(3)will表示某種傾向或習(xí)慣性動作，可以表示一種習(xí)慣性的動作，有“總是”或“會要”之意 Fish will die out of door won’t 。(1)should作為情態(tài)動詞可以表示“建議”或“勸告”，有“應(yīng)該”之意，如：You should learn from each other.(2)should后接完成式表示過去沒有做到本來應(yīng)該做的事情，或是做了本來不應(yīng)該做的事情。他竟然是我最喜愛的演員。Stay at home in case he should e to visit 。你還要告訴其他學(xué)生要帶筆，還有他們不能遲到。用于第二，三人稱的陳述句是表示說話人(并非主語)的意志或愿意，含命令，許諾，威脅等含義。(3)needn39。例如：Ought you smoke so much? You oughtn’t smoke so 、dare的基本用法(l)dare(dared為其過去式)作情態(tài)動詞用時，主要用于否定句，疑問句和條件從句中，如：Dared he bread the traffic regulations again?(2)在現(xiàn)代英語中dare常用作行為動詞，其變化與一般行為動詞相同，如：She dares to stay at home alone at 、need的基本用法(1)need作情態(tài)動詞用時，主要用于否定句和疑問句中，如：He needn39。例如：You ought to have helped him.(but you didn’t)這時，ought與 should可以互相換用。t have to).不，不必今天交。No , you needn39。t意思是“絕不能、一定不要”，而沒有“不必”的意思。t 或是don39。t do the work well that might have done it better.(3)must后接完成式的用法：表示對過去某事的推測，認為某事在過去一定做到了，如：Liu Dong isn’t in the must have gone to the 、have to 的基本用法：have to和must的意義相近，只是 must側(cè)重表示說話人的主觀看法，而have to 則表示客觀需要注意：在這種用法中，回答以must引導(dǎo)的問句時，若是否定答復(fù)，不可以用mustn39。s too could have answered it earlier, I am sure.(2)may, might后接完成式的用法①表示對過去某事的推測，認為某一件事情在過去可能發(fā)生了。 know his father has just bought him a new 、can, could, may, must后接完成式的用法(1)can, could后接完成式的用法：①在否定句或疑問句中表示對過去發(fā)生過的事情的“懷疑”或“不肯定”的態(tài)度，Could he have said so? ②在肯定句中，可以表示過去可能做到而實際并沒做到的事情，有“勸告”或“責(zé)備”的語氣。t(don39。t，因為mustn39。t(doesn39。t touch the fire.(2)對以must提出的疑問句，如作否定回答時，要用needn39。如：May I use this dictionary?Yes, ，如果Might I…? 就比用May I…? 語氣更婉轉(zhuǎn)些，如：May I have a look at your new puter? 但是表示“阻止”或“禁止”對方做某事時，要用must not代替may not，如：May we swim in this lake?No, you mustn’’s too dangerous.(2)may或 might都可以表示可能性，表示“或許”、“可能”之意，如果用might表示可能性，則語氣更加不肯定，如：They may(might)be in the library 、must的基本用法(1)must表示“必須”、“應(yīng)該”之意，其否定式 must not，縮寫形式為 mustn39。May you be happy！祝你幸福！(1)表示允許或征詢對方許可，有“可以”之意，如：You may use my “可以做某事”或“不可以做某事”時，一般多不用may或 may not，以避免語氣生硬或不容氣。If that is the case, we may as well 、祈求、祝愿，?？勺g為祝愿。當(dāng)然may 和might又都有一些各自不同的獨特用法。但是can只能有現(xiàn)在式和過去式，而be able to則有更多的形式，如：He will be able to do the work “經(jīng)過努力才得以做成功某事”時應(yīng)用be able to，不能用Can。現(xiàn)將各情態(tài)動詞的基本用法分述如下：can和could(could為can的過去式)的基本用法(1)表示能力，如：He can speak English better than you.(2)在疑問句和否定句中表示“懷疑”、“猜測”或“可能性”，如：Can this green bike be Liu Dong39。只有情態(tài)動詞ought要和帶to的動詞不定式連用，在句中作謂語用。情態(tài)動詞沒有人稱和數(shù)的變化。You could have done better if you had worked harder at ，本來可以干得更好一些的。I could e earlier if ，我可以來早一點。m afraid that we couldn39。而是could自己獨特的用法。Where could / can the boy be now ? 那孩子現(xiàn)在能在哪兒呢？另外，could還常用于表示較客氣委婉的看法、提問及用于虛擬語氣的結(jié)構(gòu)中。t / can39。t be so stupid to do 。Can you tell me how to get to the airport ? 你能告訴我怎么去機場嗎？Could you tell me how to get to the airport ?您能告訴我怎么去機場嗎？Could I be forgiven my negligence ? 請原諒我的疏忽，行嗎？4）（用于否定句、疑問句或感嘆句中）表示猜測、懷疑或驚詫How can / could you be here ? 你怎么會在這兒？She couldn39。Such kind of thing can39。When the storm stopped , the plane could take ，飛機可以起飛了不得。A more suitable person than him for the job c