Have to的用法都有哪些
ave to 是一個比較特殊的情態(tài)習語，雖然也具有情態(tài)動詞的功能，但卻與其他的情態(tài)動詞不同。它有人稱、數(shù)和時態(tài)的變化，其否定式和疑問式的構成方式也與情態(tài)動詞不一樣。同學們在使用have to 時必須弄清它的真面目，否則容易出錯。Have to的用法有哪些呢?本文是學習啦小編整理Have to的用法的資料，僅供參考。
Have to的用法
have to表示客觀需要做的事情,意思是“必須”、“不得不”.后跟動詞原形,有人稱、
時態(tài)和數(shù)的變化,與情態(tài)動詞 must 近義.
一、 have to 的陳述句形式
A、 肯定式：have to + 動詞原形
1、 I have to tidy my room.我得整理房間.
2、 She has to help with the washing.她得幫忙洗衣服.
B、 否定式：don't (doesn't) + haveto + 動詞原形
1、You don't have to go if you don't want to.如果你不想去,你就不必去.
2、He doesn't have to stay at home all day.他不必整天呆在家里.
二、have to 的一般疑問句形式及簡略答語
have to的一般疑問形式必須借助助動詞 do 或 does：
1、 Do you have to look after your sister?你得照看你妹妹么?
Yes,I do./ No,I don't.是的,我得照看./不,我不必照看.
2、 Does Jim have to do his homework?吉姆必須做家庭作業(yè)么?
Yes,he does./ No,he doesn't.是,他必須做./不,他不必做.
三、haveto 的特殊疑問句形式
1、 What do you have to do on Sundays?在星期天你得干什么?
2、 Why does she have to move to Paris?她為什么得遷往巴黎?
3、 Where do they have to work?他們必須在哪里工作?
四、haveto 可用于各種時態(tài)
A、一般現(xiàn)在時：I have to visit Mr Wang tomorrow.
明天我得去拜訪王先生.
B、一般過去時：That night we had to walk home because there was no bus.
那天晚上我們不得不步行回家,因為沒有公共汽車.
C、一般將來時：We'll have to ask Zhang Ming instead.
我們得請張明代替.
D、與may 連用：I think he may have to help his Dad in the garden.
我想他可能得在花園里幫他爸爸干活.
五、have to 與 must 的用法區(qū)別
A、 have to 比較強調客觀需要,而 must 著重說明主觀看法.
1、 My mother is ill.I have to look after her at home.
媽媽病了,我得在家照看她.
2、 You must finish your homework first.
你必須先完成作業(yè).
B、 have to 有時態(tài)和人稱變化,而 must 則沒有.
1、 Mary has to water the trees.
瑪莉得澆樹.
2、 He must bring a picnic tomorrow.
他明天得帶野餐.
C、must 有“推測”之意,而 have to 則沒有.
He must be in the classroom.
他一定在教室里.
have to 的用法
一、have to 與其他情態(tài)動詞一樣也是后接動詞原形，表示外界的
強制作用，強調被迫性。含有不情愿的色彩，常譯為“必須，不得不”。
二、have to 可用于多種時態(tài)，而且不同時態(tài)使用不同的形式：一般現(xiàn)在時中，主語為第三人稱單數(shù)時用has to 一般過去時中，用 had to。 have to 還可以用在其他的情態(tài)動詞之后。例如： I have to do some washing. 我必須洗洗衣服。 She has to look after her little sister. 她不得不照顧她的小妹妹。 I had to do my homework last night. 昨晚我不得不做作業(yè)。 I think he may have to help his Dad in the garden. 我想他可能不得不在花園里幫他爸爸。
三、have to 的否定式和疑問式一般要借用助動詞do的適當形式構成。have to 的否定式是don’t have to; has to 的否定式是doesn’t have to; had to 的否定式是didn’t have to。have to的疑問式同樣也借用助動詞do的相應形式構成。例如： He doesn’t have to do the homework now. 他沒有必要現(xiàn)在做作業(yè)。 —Do I have to go there now? 我現(xiàn)在就得去那兒嗎? —Yes, you do. (No, you don’t have to.) 是的，你必須去。(不，你不必。) We didn’t have to answer the question yesterday. 昨天我們沒有必要回答這個問題。
注：情態(tài)習語是助動詞、不定式或副詞的組合。
四、翻譯下面的句子。
1.我們必須自己動手去做。
2.瑪麗必須在英語學習上努力嗎?
3.上周日他不得不早起。
4.你沒必要為你的功課擔心。
5.彼得很累，不得不坐下來休息一會兒。
6.昨天他不得不待在家里。
7.他不得不跑回學校取他的作業(yè)本。
8.你必須早些離開嗎?
9.我沒必要躺在床上。
10.我們必須認真聽老師講課。
keys:
1. We have to do it ourselves.
2. Does Mary have to study hard at English?
3. He had to get up early last Sunday.
4. You don’t have to worry about your lessons.
5.Peter was very tired and he had to sit down and have a rest.
6. He had to stay at home yesterday.
7.Hehad to run back to school to get his exercise-books.
8. Did you have to leave early?
9. I don’t have to stay in bed.
10.We have to listen to the teachers carefully.
must和have to用法比較講解
(1)must表示“必須”，“應該”。否定式must not(mustn't)表示“不應該”，“不許可”，“不準”,“禁止”等。在回答帶有must的問句時，否定式常用need not(needn't)或don't have to 表示“不必”，而不用must not (mustn't)。 The work must be finished as soon as possible.這件工作必須盡快完成。 You mustn't speak like that.你不能那樣說話。
—Must I be home before eight o'clock? 8點之前我必須回家嗎?
—Yes, you must./No, you needn't./No, you don't have to. 是的，必須回家。/不，不必了。
(2)must表推測，
?、僖话阒挥糜诳隙ň渲?，譯成漢語“一定”，“必定”。
There must be some mistakes.肯定有一些錯誤。
You must be very tired.你一定很累了。
?、谌绻硎緦^去事情的推測，就用"must+完成時"。
You must have left your umbrella in the theatre.你一定把雨傘丟在劇院里了。
His car is still here. He must have gone by bus.他的車還在這里，他一定乘公共汽車走了。
③當must表推測之意時，其否定形式常用can not而不用must not。
He can't have been to your home. He doesn't know your address.他不可能到過你家，因為他不知道你的住址。
What can he be doing at this time of night?夜晚都到這個時候了，他究竟在干什么呢?
(3)must表必然性
You must catch cold if you don't put on more clothes.如果你不多穿些衣服，必然感冒。
All men must die.人固有一死。
Truth must be out.真相總會大白。
(4)have to表示“必須”，“不得不”，在這個意義上與must很接近，但must表示的是說話人的主觀看法，而have to 表示的卻是客觀需要。
I have to go now.我得走了。(客觀需要)
I must go now.我必須走。(主觀看法)
You have to work hard to make a living.為了謀生你就得努力工作。(客觀需要)
You must do what I tell you.你必須按照我告訴你的去做。(主觀要求)
(5)have to 有更多的時態(tài)形式：現(xiàn)在時，過去時，將來時等，而must只有現(xiàn)在時形式。
We had to be there at 8.我們得8點到那里。
I shall have to go to school tomorrow.明天我得去上學了。
(6)have to 不能代替表推測的must，但在虛擬條件句中用had had to+動詞原形表示與過去相反的情況。
You must be joking.你一定是在開玩笑。(不能用have to)
If I had had to do the work, I should have done it in a different way.
如果我不得不做這項工作，我會以不同的方式去做。(不能用must)
If I had had to run the factory, I would have had it run by able men.如果我得管理那家工廠的話，我就會讓能人來管。(不能用must)
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