On hills, he must use low gears.

在山上，他必须用低速挡。

《柯林斯英汉双解大词典》

That is the forfeit he must pay.

那是他必须付的罚金。

《柯林斯英汉双解大词典》

He must have put on several kilos.

他体重一定增加了好几公斤。

《牛津词典》

If a drafted man could not do either thing, then he must join the army or be shot as a deserter.

VOA: special.2009.10.29

If a person has the basic concept down, regardless of numerical errors, if the person has the basic concept down, he or she must get at least five out of ten.

如果一个人有一些基本的概念，不管一些数字上的错误，如果他有基本的概念，至少都能够得到一半的分。

麻省理工公开课 - 固态化学导论课程节选

to be talking about how he must be so crazy and weird and everything, and

在谈论说他一定很疯狂，很怪异等等，

印象深刻的展示会 - SpeakingMax英语口语达人

She also said he must be courteous to witnesses and not get personal with them.

NPR: Fort Hood Suspect To Represent Himself At Trial

He said he had no recollection of the fall but believes he must have landed face-first.

BBC: Fall victim's skull repaired using stomach fat injections

Or he must make a full-throated defense of British membership that categorically rules out an exit.

WSJ: The EU Waiting Game Is Over For Cameron