must和have to的用法
must和have to都有'必須'的意思,用來說明做某事的必要性,但是,二者在用法上有一定的區(qū)別。
1. must表示主觀的義務(wù)和必要,主要用于肯定句和疑問句,有'必須,得,要'的意思。
例如:I must finish my homework tonight.我今晚必須要完成家庭作業(yè)。
2. must的否定式是mustn't,表示禁止,不能,
You mustn't smoke here.你不能在這里吸煙。
3.must表示猜測,意思是'一定'
主要指客觀條件使做某事是必要的,不得不,必須,側(cè)重客觀影響。
如:I have to look after my sister on Sunday.
我星期天不得不照顧我的妹妹。
1.have to 的否定式是:don't/doesn't/didn't have to,表示不必
Jim doesn't have to go.吉姆不必走。
2.一般疑問句:
Do/Does/Did +主語+have to +動詞原形+其他?
Do I finish my homework now? 我現(xiàn)在必須要完成家庭作業(yè)嗎?
【注意】must和have to表示'必須',當(dāng)表示'不必'時,通常用don't / doesn't have to,而不用mustn't,因為mustn't 意為'禁止',表示命令或勸告。例如:
—Must I finish the work today? 我今天必須要完成這項工作嗎?
—No, you don't have to. 不,不必。
單項選擇
( )1. —Mike, you ______ swim here. It's dangerous!
—Sorry, I won't.
A. must B. needn't C. may D. mustn't
( )2. My father ______ walk to school when he was young.
A. had to B. mustn't C. must D. didn't have to
( )3. —Must I finish doing my homework tonight?
—______. You can do it tomorrow.
A. Yes, you must B. No, you don't have to
C. Yes, you can D. No, you mustn't
參考答案:1.D 2.A 3. B
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