But now, when you need more, you can't just say I only want the best bottom land there is.

然而当你需要更多土地时,你不能张口就要这片地区最富饶的土地

耶鲁公开课 - 古希腊历史简介课程节选

When you say "I must" what you mean is "I need to do something."

当你说 "I must"的时候，你是指“我必须得做某事。”

Must 课堂 - SpeakingMax英语口语达人