1. have an ax to grind 心懷叵測
如：She always has an ax to grind. You should take whatever she says with a pinch of salt.
她總是心懷叵測，對她說的話你得多留神 。
have one’s heart in the right place 心數不正
如：He doesn’t have his heart in the right place. He would find every opportunity to stab in the back of others.
他的心數不正，動不動就在別人的背後捅刀子。
3. stab in the back 背後捅刀子
如：I was taken aback and didn’t think Zhang would stab me in the back. I placed too much trust in her.
我萬萬沒想到張某會在背後捅我一刀。我過去太信任她了。
4. badmouth somebody 說某人的'壞話
如：I’ve never badmouthed anyone.
我從來沒說過任何人的壞話。
5. smite with the tongue 血口噴人
如：Don't offend her. She always smites with the tongue.
千萬別得罪她，她經常血口噴人。
k with one’s tongue in one’s cheek 假惺惺的說
如：I feel sick of her. She always speaks with her tongue in her cheek.
我特別討厭她。她說話總是假惺惺地。
7. go back on one’s words 說話不算數
如：We cannot account on him. He always goes back on his words.
他那個人說話從不算數,我們可不能依靠他。
8. bite the hand that feeds one 恩將仇報
如：Don’t you know she’s the one that would bite the hand that feeds her?
你難道不知道她是個恩將仇報的人？
the gall to do 厚着臉皮去幹
如：How can you have the gall to complain about other people’s being lazy?
你怎麼能厚着臉皮去抱怨說別人不勤快？
發牢騷
如：I’m really bored with his sitting there doing nothing but beefing.
他坐在那裏什麼事也不幹，總是發牢騷，真煩死人。