watch your mouth 注意你的言辞，当心你的嘴巴

Watch your mouth! What you say is terrible!

注意你说话的态度!你说的话糟糕透了!

Watch your mouth. Do you know who you're talking to?

说话小心一点，你知道你在和谁说话吗?

You'd better watch your language, Mr Yuyu.

你最好注意一下你的措辞，Yuyu先生!