Say one thing and do another. (来源：英语杂志 http://www.EnglishCN.com)

     6. 一言既出，驷马难追：有人译成：One word lets slip and four horses will fail to catch it. 或 A statement that once let loose cannot be caught by four galloping horses.

     这两种说法，中文味道嫌重，老外未必理解。不过他们倒有类似的说法：

     A word once let go cannot be recalled.

     或者说：

     You can not take back what you have said. (你说出的话，就不能再收回来。)

     7. 祸从口出，言多必失：有人译为：The mouth is the gate of misfortune and evil.

     老外听了，恐怕不能完全理解。最好说成：

     Careless talk leads to trouble. (不小心说话，会带来麻烦); 或

     The less said the better. (说的愈少愈好)

     甚至也可以说：

     Shut the mouth and open the eyes. (闭嘴少说，张眼多看。) 摘自：旺旺英语