1. Hit the roof
也可以说，go through the roof，等于中文里的“火冒三丈，暴跳如雷”
When I was expelled from school, my parents went through the roof.
2. Let the cat out of the bag
你让别人keep sth to yourself（对（某事）保守秘密），结果他let the cat out of the bag（无意中泄秘，说漏嘴）。
I was trying to keep the party a secret, but Mel went and let the cat out of the bag.
3. A rip off
The 100-dollar jacket is such a rip off!
4. Water under the bridge
Yes, we did have our disagreements but that's water under the bridge now.
You're cold - look, you've got goosebumps!
6. Go on about sth
I just wish he'd stop going on about how brilliant his daughter is." "Yes, he does go on (a bit), doesn't he?"
7. have it in for sb
She's always had it in for me.
8. Kiss and make up
吵架之后言归于好就是“kiss and make up”。
They had an argument last week about the new house, but they’ve kissed and made up now.
9. clutch/grasp at straws
clutch通常指（因恐惧、焦虑或痛苦而）紧抓，紧握，grasp也是紧握的意思，straw的意思是禾秆；麦秆；稻草，clutch/grasp at straws形容（为摆脱困境）抓救命稻草，不放过任何微小的机会。
She offered to take a pay cut to keep her job, but she was just clutching at straws.
10. cross your fingers
也可以说keep your fingers crossed，这是在祈求好运。
We're keeping our fingers crossed that the weather stays nice.
11. Get the sack
Get the sack是被解雇，解雇某人就是give an the sack。
They gave him the sack for being late.
12. Better safe than sorry
Drive safely. Better safe than sorry!
13. Make sb’s day
Seeing Adrian again after such a long time really made my day.