You'd better button your lip.

　　你最好闭上嘴。

　　button one's lip 字面意思是：“用纽扣扣上嘴唇”，这个习语的真正意思当然不是如此，像多数习语一样，这是个比喻的说法，扣上嘴巴后嘴巴就不能张了，也就表示：“闭嘴，住口，保持沉默”。因此，当美国人说"You'd better button your lip."时，他/她要表达的意思就是:"You'd better shut up."、"It's wise for you to keep silent on this topic."。

　　情景对白：

　　Colleague: Excuse me, I can hardly grasp what you're talking about. What financing cost?

　　同事：不好意思，我不懂你们在说什么。什么融资成本？

　　Boss: Oh, boy, you'd better button your lip if you are not quite familiar with this business.

　　老板：哦，伙计，如果你不是很清楚这块业务，你最好闭上嘴。

　　搭配句积累：

　　①I agree to take actions to prevent the loss immediately.

　　我同意立即采取措施以预防损失。

　　②We should put more money into this project.

　　我们应该在这项工程上加大投资。

　　③Perhaps we should buy that company as soon as possible.

　　或许我们应该尽早收购那家公司。

　　④It's none of your business.

　　不关你的事。

　　单词：

　　button vt. 用纽扣扣上

　　Ferguson stood up and buttoned his coat.

　　弗格森站起身来，扣上了外套。

　　It's very warm, he didn't even button his coat.

　　天气很暖和,他甚至都没扣他外衣的钮扣。

　　The young man slipped on the shirt and buttoned it up.

　　这个年轻人一下子穿上衬衫，扣好了扣子。