have/keep your wits about you
Be able to think quickly and make sensible decisions
保持头脑冷静；随机应变
- Cycling is potentially very dangerous in the city - you have to keep your wits about you.
在城里骑自行车可能会非常危险——你必须保持清醒的头脑。
know what’s what
Know the important facts about a situation
懂行；老练
- Linda's been in the business for 30 years - she knows what's what.
琳达从事这一行已有30年了——她很懂行。
not have a leg to stand on
Not have any way of proving that you are right about something
没有依据，无法证明
- If you have no witnesses, you don't have a leg to stand on.
如果没有证人，你就无法证明。
slow on the uptake
Taking a very long time to understand or realize something
领悟得快/慢
- He's a little slow on the uptake, so you may have to repeat the instructions a few times.
他领悟力比较差，因此你可能得重复指导他好几遍。
(drive sb) round the bend
Crazy; insane
使…厌烦；使…生气
- Staying at home all day was driving her around the bend.
整天呆在家里，快把她憋疯了。
split hairs
Argue or worry about very small details
纠缠于细枝末节；在鸡毛蒜皮的事上争论不休
- Don't split hairs. You know what I'm getting at.
别钻牛角尖了。你知道我指什么。
go to your head
To cause one to become arrogant
冲昏头脑，使骄傲自满
- Don't let fame/success go to your head.
别让名声/成功冲昏你的头脑。
go to one's head一般还用于表达喝酒上头、微醉等。
- Champagne always goes straight to my head.
香槟总是把我弄得头昏脑胀。
ring a bell
To seem familiar, although you cannot remember the exact details
听起来耳熟；（心里）有印象
- No, I'm sorry, that description doesn't ring any bells with me.
不！很遗憾，那个说法我听起来并不耳熟。
in the dark
Not knowing very much about something
蒙在鼓里，浑然不知
- I managed to keep my parents in the dark about this.
我设法对父母瞒下了此事。
