get off sb’s back

　　To stop annoying sb., for example by criticizing them, or asking them to do sth.

　　这个看英文解释比较简单明了。如果一个人总是对你品头论足或者一个劲儿的告诉你做着做那，你就可以吼上一句：

　　Just get off my back, will you!

　　have a bone to pick with sb.

　　To be angry with sb. about sth. and want to discuss it with them.

　　这个如果非得翻译成中文的话，可以解释为“咱俩得说道说道”，或者“咱俩得谈谈”。当然，按照字幕组的翻译“和你好好理论下”也是非常传神滴!

　　give sb. a hard time

　　To deliberately make a situation difficult and unpleasant for sb.

　　就是“故意刁难为难某人”。

　　They really gave me a hard time at the interview.

　　这个用法也有第二个意思，即：to criticize someone and make them feel guilty about something that they have done。有种“给某人脸色看”的意思，不过这个是因为对方做了不该做的事儿，比如：

　　I came home late one night last week and she’s been giving me a hard time about it ever since.