(past had to 或［间接引语中 ］must)
1
- be obliged to; should (expressing necessity)表示必要必须：
I must go
我必须去
it mustn't be over 2,000 words
字数不得超过2,000
she said she must be going.
她说她必须要走了。
1.1
- expressing insistence表示坚持一定：
you must try some of this fish
这鱼你一定要尝一点儿
if you must smoke you could at least go in the living room.
如果你一定要抽烟的话, 至少你可以到客厅里去。
1.2
- used in ironic questions expressing irritation［用于具有讽刺意味的问句中表示恼怒 ］一定要, 非要：
Charlotte, must you put spanners in the works?
夏洛特, 难道你非捣乱不可吗？
2
- expressing an opinion about something that is logically very likely表示合乎逻辑的推断 一定, 想必：
there must be something wrong
一定是出了什么差错了
you must be tired.
你一定是累了。
- informal something that should not be overlooked or missed〈非正式〉不该忽视（或不可错过）的东西; 必备之物：
this video is a must for everyone.
这录像每一个人都该看看。
短语
词源
Old English mōste, past tense of mōt 'may', of Germanic origin; related to Dutch moeten and German müssen.
词源
Old English, from Latin mustum, neuter (used as a noun) of mustus 'new'.
(亦作musth)
mass noun
- the frenzied state of certain male animals, especially elephants or camels, that is associated with the rutting season（尤指发情期的公象、雄骆驼等的）狂暴状态：
a big old bull elephant in must
处于发情期狂暴状态的大老公象
as modifier the must gland.处于发情期狂暴状态的腺体。
词源
late 19th cent.: via Urdu from Persian mast 'intoxicated'.