(一).It's a deal.就这么办吧。

This means "agree to your offer." Often the speakeris saying that he and another per. son have agreedon the cost of something that is being bought andsold.

原音重现：

A: If you pay me $7000, I'll sell you the car.

你出7000美元我就把车卖给你。

B: It is a deal. I need to go to the bank first.

成交，我先去下银行。

(二).A deal's a deal.这是约好的。

This means that a person can't change an agreement that was made. It is a way to say "Youhave to honor the agreement you made with me."

原音重现：

A: I don't want to buy the car now.

我现在不想买车了。

B： You must. A deal's a deal.

你一定得买，不是约好了吗?

美剧表达：

We have made the changes you asked for and it's a done deal.

我已经按你的要求改好了，就照约定的做吧