at one's wits' end

1. 全然不知所措

I am at my wits' end to know what to do with my son.

我真不知对我儿子该怎么办才好。

have/keep one's wits about one

1. 保持警觉

In this part of the city you have to keep your wits about you all the time.

在该城市的这一地区你一定得随时保持警觉。

live by one's wits

1. 靠施展小聪明过日子

I knew a fellow who lived for years by his wits.

我认识一个人, 好多年来他就靠施展小聪明过日子。

out of one's wits

1. 发疯

You'll drive me out of my wits if you go on behaving in this way.

你再这样下去真要把我逼疯了。

to wit

1. 即

He and all his family -- to wit, mother, father, three brothers, and one dog -- were waiting for me at the station.

他及其全家, 即母亲, 父亲, 三个兄弟, 还有一条狗, 都在车站接我。