新一輪中考復(fù)習(xí)備考周期正式開始，初中升學(xué)網(wǎng)為各位初三考生整理了各學(xué)科的復(fù)習(xí)攻略，主要包括中考必考點、中考常考知識點、各科復(fù)習(xí)方法、考試答題技巧等內(nèi)容，幫助各位考生梳理知識脈絡(luò)，理清做題思路，希望各位考生可以在考試中取得優(yōu)異成績！下面是《2018中考英語知識點：助動詞用法講解》，僅供參考！

　　助動詞用法講解　　助動詞一般沒有詞意，不能單獨作謂語動詞。其作用在于幫助構(gòu)成各種時態(tài)、語態(tài)、否定、疑問等。　　1、助動詞be（am, is, are, was, were, being, been）的用法　?。?） be后跟現(xiàn)在分詞構(gòu)成進(jìn)行時態(tài)?！　ho is playing the violin?誰在拉小提琴？　　She was reading a book then.那時她正在讀書。　?。?）be后跟過去分詞構(gòu)成被動語態(tài)。　　He was asked to do the work.有人要他干這件工作?！　ou are invited to attend the meetintg.有人邀請你參加會議?！　。?）be 后跟不定式作謂語，有如下幾種情況：　　①表示計劃、安排將要發(fā)生的事?！　ho are we to meet?我們要見誰呀？　　I'm to have supper with John this afternoon.今天下午我要與約翰一起吃晚飯。　　②表示指示、命令，否定式表禁止?！　ou are to see the headmaster today.今天你必須去見校長。　　You are not to enter the room without permission.未經(jīng)允許你不能進(jìn)入房間。　　③表示義務(wù)、責(zé)任等，同should?！　ou are to be back before 5.你得在5點鐘以前回來。　　What is to be done?該干什么。　?、鼙硎究赡苄?，與情態(tài)動詞may, can同義。　　Such books are to be found in any library.這種書任何圖書館都有?！　ot a sound was to be heard.一點聲響也沒有?！　、荼硎竞髞戆l(fā)生的事，可以用來表示命運或注定　　They say good-bye, little knowing that they were never to meet again.他們告別了，沒想到再也不能相見了?！　e was to regret the decision.他有一天會后悔做出這一決定的?！　、抻糜诹?xí)語　　Where am I to go? 我該向何處去？　　What am I to do? 我該怎么辦？　　2、助動詞have(has, had, having)的用法　?。?）助動詞have可以構(gòu)成完成時或完成進(jìn)行時　　He has been a doctor for 10 years.他當(dāng)醫(yī)生十年了。　　This is the place I have been longing to visit.這就是我一直渴望參觀的地方?！　。?）和不定式構(gòu)成謂語，表示客觀上不得不做的事情?！　e've missed the train. We'll have to wait for another one.我們己經(jīng)誤了火車，我們只能等下一列?！　?Do we have to start work?我們得立刻工作嗎？　　-No. We don't have to.不，不必了?！　?、do(does, did) 的用法　?。?）構(gòu)成疑問句或否定句　　How did you know about it?你是怎樣知道這件事的?！　e does not smoke. 他不抽煙。　　（2）加強(qiáng)語氣?！　e did tell that.他的確告訴了此事。　　Do come and see us.一定來看我們?！　。?）代替前面剛出現(xiàn)的動詞，避免重復(fù)?！　?You like popular music, don't you?你喜歡流行音樂，是吧？　　-Yes , I do.是的，我喜歡?！　e speaks French as fluently as she does.他講法語和她講的一樣流利。　?。?）用于倒裝句中?！　ever did he pay attention to my words.他從不注意我的話。　　only then did I understand the importance of English.只是那時，我才了解到英語的重要性。　?。?）構(gòu)成否定的祈使句。　　Don't be so careless.不要那么粗心。　　Do not hesitate to come for help.只管來求助。　　4、shall(should)和will(would) 的用法　?。?）shall(should)用于第一人稱的將來時中，單純表示來　　I shall think it over.我要好好考慮一下?！　hen shall I see you again?我何時再見到你？　　I rang up to tell her that I should leave for London. 我打電話告訴她我要去倫敦。　?。?）will用于第二、第三人稱的將來時態(tài)中，在現(xiàn)代英語中可以用于所有人稱　　He will be 30 next month. 他下月將是30歲?！　ou will have an English test tomorrow.明天你有英語小測驗?！　e wanted to know when you would finish the writing.他想知道你何時完成寫作。