You must signal which way you are going to turn.

　　你要朝哪個(gè)方向轉，必須發(fā)出信號。

　　You're a great help, I must say!

　　我得說(shuō)，你可沒(méi)少幫忙！

　　There must be a way around the problem.

　　肯定有解決這個(gè)問(wèn)題的辦法。

　　The work must be completed within a certain time limit.

　　這項工作必須在一定期限內完成。

　　There is a growing realization that changes must be made.

　　越來(lái)越多的人認識到改革勢在必行。