新東方網小編給各位初三考生整理了各學科的複習攻略，本文是初中英語知識點總結：助動詞用法講解，幫助各位考生梳理知識脈絡，理清做題思路，希望各位考生可以在考試中取得優異成績!
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。其作用在於幫助構成各種時態、語態、否定、疑問等。
1、助動詞be(am, is, are, was, were, being, been)的用法
(1) be後跟現在分詞構成進行時態。
Who is playing the violin?誰在拉小提琴?
She was reading a book then.那時她正在讀書。
(2)be後跟過去分詞構成被動語態。
He was asked to do the work.有人要他幹這件工作。
You are invited to attend the meetintg.有人邀請你參加會議。
(3)be 後跟不定式作謂語，有如下幾種情況：
①表示計劃、安排將要發生的事。
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.未經允許你不能進入房間。
③表示義務、責任等，同should。
You are to be back before 5.你得在5點鐘以前回來。
What is to be done?該幹什麼。
④表示可能性，與情態動詞may, can同義。
Such books are to be found in any library.這種書任何圖書館都有。
Not a sound was to be heard.一點聲響也沒有。
⑤表示後來發生的事，可以用來表示命運或註定
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.他有一天會後悔做出這一決定的。
⑥用於習語
Where am I to go? 我該向何處去?
What am I to do? 我該怎麼辦?
2、助動詞have(has, had, having)的用法
(1)助動詞have可以構成完成時或完成進行時
He has been a doctor for 10 years.他當醫生十年了。
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. 他不抽菸。
(2)加強語氣。
He did tell that.他的確告訴了此事。
Do come and see us.一定來看我們。
(3)代替前面剛出現的動詞，避免重複。
-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)用於倒裝句中。
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，我才了解到英語的重要性。
(5)構成否定的祈使句。
Don't be so careless.不要那麼粗心。
Do not hesitate to come for help.只管來求助。
4、shall(should)和will(would) 的用法
(1)shall(should)用於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。
When 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。
(2)will用於第二、第三人稱的將來時態中，在現代英語中可以用於所有人稱
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。
He wanted to know when you would finish the writing.他想知道你何時完成寫作。