三、must, have to的用法
1. 兩詞都是“必須”的意思，have to 表示客觀的需要，must 表示說話人主觀上的看法，即主觀上的必要。
如：My brother was very ill, so I had to call the doctor in the middle of the night.
我弟弟病得很厲害，我只得半夜裡把醫生請來。(客觀上需要做這件事)
He said that they must work hard. 他說他們必須努力工作。（主觀上要做這件事）
2. have to有人稱、數、時態的變化，而must只有一種形式。
如：He had to look after his sister at home yesterday. 昨天他不得不在家照看妹妹。
3. 在否定結構中：don't have to 表示“不必”
mustn't 表示“禁止”，
如：You don't have to tell him about it. 你不一定要把此事告訴他。
You mustn't tell him about it. 你一定不要把這件事告訴他。
—Must I finish the homework right now?
我現在必須完成家庭作業嗎？
—Yes, you must. / Yes, you have to. 是的。
(—No, you needn’t. / No, you don’t have to. 不，不必。)
4. must be+表語，表示推測，它的否定和疑問形式用can代替must。
如：This must be your pen. 這個一定是你的鋼筆。
Your sister must be a doctor in this hospital. 你姐姐一定是這家醫院的醫生。
Exercise
1. Come on! We __________ hurry because there isn't much time left.
A. may B. must C. can D. need
2. Amy did best in the English test. She __________ hard last week.
A. must have been working B. should have worked
C. should work D. must work.
四、should的用法
（1）用來提供幫助、提出建議，要求對方給出意見。
如：Should I help you with the community affairs? 我可以幫你做一些社區事務嗎？
Should we clean the classroom now? 現在我們可以打掃教室嗎？
（2）表達義務、職責等。
如：I think today’s children should really learn to respect their elders.
我認為今天的孩子應該好好學習尊敬長輩。
You should （= ought to ） tell your mother about it at once. 你應該立即把此事告訴你媽媽。
He should work harder. 他應該更加努力。
You should help your mother with the housework. 你應該幫你母親做家務。
例. Look out! The knife is very sharp. You ______ cut your finger.
A. need B. must C. should D. may
五、will, would的用法
1. 表示“將、將要、自願做…”等。
如：People will die without air or water. 人離開水和空氣將會死的。
I will do my best. 我將會盡力而為。
2. would like； Would like to do = want to 想要，為固定搭配。
如：Would you like to go with me? 你想和我一起走嗎？
3. Will you…? Would you like…? 表示肯定含義的請求勸說時，疑問句中一般用some, 而不是any。
如：Would you like some cake? 你想要一些蛋糕嗎？
Exercise 5
1. ______ I know your name?
A. May B. Will C. Shall D. Must
2. What kinds of homes will we live in the future? Nobody ______ be sure, but scientists are working out new ideas now.
A. will B. may C. can D. must
六、had better的用法
表示“最好”，相當於一個助動詞，只有一種形式，後面要跟動詞原形，否定詞形式為had better not。
如：It is pretty cold. You’d better put on my coat. 天很冷，你最好把我的大衣穿上。
You had better go now你最好現在就走
He'd(=He had) better do it now他最好現在做
She'd better not cry她最好別哭
例. You ____ your tooth pulled out before it rot completely.
A. had better got
B. had to get better
C. had better to get
D. had better get
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