1. have an ax to grind 心怀叵测
如：She always has an ax to grind. You should take whatever she says with a pinch of salt.
2.not have one’s heart in the right place 心数不正
如：He doesn’t have his heart in the right place. He would find every opportunity to stab in the back of others.
3. stab in the back 背后捅刀子
如：I was taken aback and didn’t think Zhang would stab me in the back. I placed too much trust in her.
4. badmouth somebody 说某人的坏话
如：I’ve never badmouthed anyone.
5. smite with the tongue 血口喷人
如：Don't offend her. She always smites with the tongue.
6.speak with one’s tongue in one’s cheek 假惺惺的说
如：I feel sick of her. She always speaks with her tongue in her cheek.
7. go back on one’s words 说话不算数
如：We cannot account on him. He always goes back on his words.
8. bite the hand that feeds one 恩将仇报
如：Don’t you know she’s the one that would bite the hand that feeds her?
9.have the gall to do 厚着脸皮去干
如：How can you have the gall to complain about other people’s being lazy?
如：I’m really bored with his sitting there doing nothing but beefing.