18. to drive (someone) up the wall：to annoy or upset someone(惹人生气或者不高兴)

　　The boy is driving his mother up the wall because of his ill behavior.

　　这个不听话的孩子让他妈妈大为头痛。

　　If you ask too many questions， you may drive your boss up the wall.

　　假如你的问题太多也会让你的老板很反感。

　　19. to write(someone or something)off：to throw away or to discard(抛弃或者丢弃);to deduct a business loss(在经商失败时，也用于报销、注销或扣除损失的数额中)

　　After a hot argument， she wrote off her boyfriend.

　　她和男朋友大吵了一架之后，就把他甩了。

　　He will write off the charitable contributions from his income taxes.

　　他从所得税中扣除了慈善募捐的金额。

　　20. to make waves：to make trouble(惹是生非，与“rock the boat”意思相近)

　　Many politicians like to make waves in order to be kept in the media.

　　许多政客为了能在媒体上路脸儿而不惜哗众取宠。

　　Teenagers tend to make waves with their parents and teachers.

　　一些青少年总是会给父母和老师惹麻烦。

　　21. to keep (one's)nose clean：to keep away from trouble(远离是非，少惹麻烦)

　　The newly released inmates are trying to keep their noses clean.

　　刚刚获释的犯人总是尽量少惹是非。

　　A law-abiding person needs to keep his (her) nose clean.

　　奉公守法的人应该避免制造麻烦。