Must is a modal verb. It is followed by the base form of a verb.
must为情态动词，后跟动词原形。The noun is pronounced /mʌst/. 名词读作 /mʌst/。
1. 必须；一定要
You use must to indicate that you think it is very important or necessary for something to happen. You use must not or mustn't to indicate that you think it is very important or necessary for something not to happen.
e.g. What you wear should be stylish and clean, and must definitely fit well...
你的穿着应该整洁漂亮，而且必须非常合身。
e.g. You are going to have to take a certain amount of criticism, but you must cope with it...
你肯定会遭到一些批评，但你必须去面对。
2. (通常因为规定或法律)必须，应当
You use must to indicate that it is necessary for something to happen, usually because of a rule or law.
e.g. Candidates must satisfy the general conditions for admission...
候选人必须满足参选的总体条件。
e.g. Mr Allen must pay Mr Farnham's legal costs...
艾伦先生应当支付法纳姆先生的诉讼费。
3. (用于表示肯定推测)一定，谅必
You use must to indicate that you are fairly sure that something is the case.
e.g. At 29 Russell must be one of the youngest ever Wembley referees...
29岁的拉赛尔一定是有史以来温布利球场上的裁判员中最年轻的一个。
e.g. Reggae must be the only music that's got its own country — Jamaica...
雷盖音乐得到了一整个国家人民的支持，这个国家就是牙买加——这一点上它无疑是独一无二的。
4. (用于表示据已知情况推测)很可能是，想必是，肯定是
You use must, or must have with a past participle, to indicate that you believe that something is the case, because of the available evidence.
must什么意思
e.g. 'You must be Emma,' said the visitor...
来客说：“你肯定是埃玛。”
e.g. Miss Holloway had a weak heart. She must have had a heart attack...
霍洛韦小姐心脏不好，她肯定得过心脏病。
5. (用于表示前者为后者的前提)应该已经(发生)
If you say that one thing must have happened in order for something else to happen, you mean that it is necessary for the first thing to have happened before the second thing can happen.
e.g. In order to take that job, you must have left another job...
为得到那份工作，你肯定已辞去了另一份工作。
e.g. In order to start reading this book you must have had some idea that the physical symptoms you were experiencing were due to anxiety.
开始读这本书之前，你一定已经了解到：你身体的不适症状是源于焦虑。
6. (用于表示意图)一定要，坚持要
You use must to express your intention to do something.
e.g. I must be getting back...
我一定要回来。
e.g. I must have a whiskey...
我要喝杯威士忌。
7. (用于表示建议或邀请)务必，一定要
You use must to make suggestions or invitations very forcefully.
e.g. You must see a doctor, Frederick...
弗雷德里克，你一定得去看医生。
e.g. You must see the painting Paul has given me as a wedding present...
你一定要看看保罗送给我作结婚礼物的那幅画。
8. (用于表示同情)必定，想必
You use must in remarks and comments where you are expressing sympathy.
e.g. This must be a very difficult job for you...
对你来说，这份工作想必很难。
e.g. You must be very worried by now...
你现在一定非常担心。
9. (用于强调)我得说/我得承认
You use must in conversation in expressions such as 'I must say' and 'I must admit' in order to emphasize a point that you are making.
e.g. This came as a surprise, I must say...
我得说这真是个意外。
e.g. I must admit I like looking feminine...
我得承认我喜欢看起来淑女一些。
10. (用于引起读者或听众的注意)一定要注意/一定记住
You use must in expressions such as 'it must be noted' and 'it must be remembered' in order to draw the reader's or listener's attention to what you are about to say.
e.g. It must be noted, however, that not all British and American officers carried out orders...
然而，一定要注意不是所有的英国和美国军官都执行了命令。
e.g. It must be stated that this illness is one of the most complex conditions known to man.
必须声明，这种疾病是人类已知的最为复杂的疾病之一。
11. (用于问句中表示生气)偏偏，非要
You use must in questions to express your anger or irritation about something that someone has done, usually because you do not understand their behaviour.
e.g. Why must you do everything as if you have to win?...
你为什么做每件事情都跟你非要赢似的？
e.g. Why must she inter-rupt?...
她为什么非要插嘴？
12. (用于感叹句，表示惊讶或震惊)一定是，准是
You use must in exclamations to express surprise or shock.
must的解释
e.g. 'Go! Please go.' — 'You must be joking!'...
“走吧！请走吧。”——“你一定是在开玩笑吧！”
e.g. I really must be quite mad!...
真的，我一定是气坏了！
13. 必不可少的事物;一定要做的事
If you refer to something as a must, you mean that it is absolutely necessary.
e.g. The new 37th issue of National Savings Certificates is a must for any taxpayer...
新发行的第37期国家储蓄债券是任何一个纳税人的必然之选。
e.g. A must is a visit to the fascinating and world-renowned Motor Museum.
一定要去参观一下那个举世闻名且精彩有趣的汽车博物馆。
14. 如果你一定要(这样做的话)
You say 'if you must' when you know that you cannot stop someone doing something that you think is wrong or stupid.
must
e.g. If you must be in the sunlight, use the strongest filter cream you can get...
如果一定要呆在太阳底下的话，就擦上你能买到的防晒系数最高的防晒霜。
e.g. 'Could I have a word?' — 'Oh dear, if you must.'...
“我能说一句吗？”——“亲爱的，如果你非说不可的话，好吧。”
15. 如果你一定想要知道的话
You say 'if you must know' when you tell someone something that you did not want them to know and you want to suggest that you think they were wrong to ask you about it.
must什么意思
e.g. 'Why don't you wear your jogging shorts Mum?' — 'Well, my legs are too skinny, if you must know.'
“妈妈，为什么不穿你的慢跑短裤呢？”——“哦，如果你非要问的话，因为我的腿太瘦了。”
e.g. 'You told him you'd been there that night.' — 'If you must know, yes.'
“你跟他说过你那天夜里去过那儿了。”——“是的，如果你非要问的话。”
