初中英語知識點(diǎn)總結(jié)：初中英語語法——助動(dòng)詞用法講解

助動(dòng)詞一般沒有詞意，不能單獨(dú)作謂語動(dòng)詞。其作用在于幫助構(gòu)成各種時(shí)態(tài)、語態(tài)、否定、疑問等。

1、助動(dòng)詞be(am, is, are, was, were, being, been)的用法

(1) be后跟現(xiàn)在分詞構(gòu)成進(jìn)行時(shí)態(tài)。

Who is playing the violin?誰在拉小提琴?

She was reading a book then.那時(shí)她正在讀書。

(2)be后跟過去分詞構(gòu)成被動(dòng)語態(tài)。

He was asked to do the work.有人要他干這件工作。

You are invited to attend the meetintg.有人邀請你參加會(huì)議。

(3)be 后跟不定式作謂語，有如下幾種情況：

①表示計(jì)劃、安排將要發(fā)生的事。

Who 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。

You 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。

You are to be back before 5.你得在5點(diǎn)鐘以前回來。

What is to be done?該干什么。

④表示可能性，與情態(tài)動(dòng)詞may, can同義。

Such books are to be found in any library.這種書任何圖書館都有。

Not a sound was to be heard.一點(diǎn)聲響也沒有。

⑤表示后來發(fā)生的事，可以用來表示命運(yùn)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。

He was to regret the decision.他有一天會(huì)后悔做出這一決定的。

⑥用于習(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(dòng)詞have(has, had, having)的用法

(1)助動(dòng)詞have可以構(gòu)成完成時(shí)或完成進(jìn)行時(shí)

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。

(2)和不定式構(gòu)成謂語，表示客觀上不得不做的事情。

We'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。

3、do(does, did) 的用法

(1)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。

He does not smoke. 他不抽煙。

(2)加強(qiáng)語氣。

He did tell that.他的確告訴了此事。

Do come and see us.一定來看我們。

(3)代替前面剛出現(xiàn)的動(dòng)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。

He speaks French as fluently as she does.他講法語和她講的一樣流利。

(4)用于倒裝句中。

Never 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(shí)，我才了解到英語的重要性。

(5)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

(1)shall(should)用于第一人稱的將來時(shí)中，單純表示來

I shall think it over.我要好好考慮一下。

When shall I see you again?我何時(shí)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。

(2)will用于第二、第三人稱的將來時(shí)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。

You will have an English test tomorrow.明天你有英語小測驗(yàn)。

He wanted to know when you would finish the writing.他想知道你何時(shí)完成寫作。