Nobody says that.What they say is, "Oh please, we need you Achilles,you must not do this."

没人这么说,他们说的是,"噢,求求你,我们需要你,阿喀琉斯,你可一定得去参战啊"

耶鲁公开课 - 古希腊历史简介课程节选

When you say "it must", this usually does not mean it needs to do something.

当你说“It must”的时候，通常并不表示它需要做某事。

Must 课堂 - SpeakingMax英语口语达人

And so the big issue is -- this is what you must never do, but this is what you got to do if your phalanx is broken.

所以现在的大问题是,这也许是你在战场上永远不能做的事,但你在方阵被打散时不得不这么干

耶鲁公开课 - 古希腊历史简介课程节选