口是心非-------speak with one's tongue in one's cheek
例句:
A: I don't know why Jack promised to back me up, but he broke his promise.
我不知道为何杰克答应支持我,却失信了。
B: Don't you know he often speak with his tongue in his cheek?
难道你不知道他经常口是心非吗?
同义词:
1.play a double game
2.say one thing and mean another