"You must always remember," one said, "that the president is about six years old."

VOA: special.2010.08.12

You must remember that this describes a particle going side to side.

务必记住,描述的是一个质点的横向运动

耶鲁公开课 - 基础物理课程节选

And there's a certain line that you must remember.

你必须记下一些台词。

I'm frustrated 课堂 - SpeakingMax英语口语达人