You've been a great help, I must say.
依我看，你真是幫了個大忙啊。
I must go to the bank and get some money.
我得上銀行取點兒錢。
He must be 70 if he's a day!
他至少70歲了！
You must signal which way you are going to turn.
你要朝哪個方向轉，必須發出信號。
You're a great help, I must say!
我得說，你可沒少幫忙！
There must be a way around the problem.
肯定有解決這個問題的辦法。