3. turn my back on 拒绝帮助

例句：I can't turn my back on him when he needs help.

在他需要帮助的时候，我不能不管。

4. behind my back 在背后

例句：If I did refuse to help, my supervisor might say bad things about me behind my back.

如果我真的拒绝帮忙，我的上司会在背后说我坏话。

5. stab in the back 伤人的暗箭；背叛；诽谤

例句：Such a vicious lie could be nothing but stab in the back.

这样的恶毒谎言简直是背地里向人捅刀子。

6. pat on the back 鼓励；表扬

例句：Sometimes, when I am very productive in my job, my employer gives me a pat on the back.

有时当我工作非常富有成效时，我老板会表扬我。

7. I will scratch your back if you will scratch mine 礼尚往来

例句：I'll scratch your back if you'll scratch mine" only works if you will respond with something approaching parity.

只有晓得对方会以接近对等的方式回应，“礼尚往来”才行得通。