1. on fire
Damn, that party was on fire.
You are on fire today.
2. get the hang of
指在经过练习之后摸清某物的用法，得知某事的窍门（to succeed in learning how to do something after practising it）
I finally got the hang of this Macbook.
3. pay through the nose
If you bring a car into the city, you have to pay through the nose for parking it.
4. feel the pinch
双十一买买买之后的你有没有感觉自己已经连土都吃不起了呢？Feel the pinch的意思是手头拮据、经济出现困难
When her husband lost his job, she really started to feel the pinch.
5. Chances are pretty good (that)...
Alone on Instagram? Chances are pretty good your pictures suck.
Got no boyfriend? Chances are pretty good you're ugly.
6. a kick in the teeth
The Government's decision is a real kick in the teeth for the unions.
Not being accepted by colleges is surely a kick in the teeth for an excellent student like Kate.
7. waiting in the wings
Wings原本是指剧院里演员等候上台的地方，字面意思是等待上台表演，如今引申为做好准备等待机遇的到来，翘首以待（to be ready to be used or employed）
They say Bob will be fired and I'm waiting in the wings to take over.
8. weak at the knees
The very thought of jumping off the bridge made him go weak at the knees.
The thought of kissing him made me go weak at the knees.
9. put your foot in your mouth
I certainly put my foot in my mouth at the party last night when I asked Mr. Brown to say hello to his wife for me. Somehow I'd forgotten that his wife died six months ago.
10. no sweat
这个俚语意思就相当于no problem，no difficulty，do not worry
Of course I can have your laptop repaired by noon. No sweat.
11. get to the bottom of something
搞清楚某事，彻查某事，对…寻根究底（to get an understanding of the causes of something）
There is clearly something wrong here, and I need to get to the bottom of it.
12. put up or shut up
要么行动要么就闭嘴，有点类似于网上流行的“You can you up, no can no bb（你行你上啊，不行别逼逼）”
You keep saying you're going to ask her out. Well, put up or shut up.