have ants in one’s pants:

看到这个短语，很多人已经都差不多猜出它的意思了，“坐立不安”，因为蚂蚁要是进入裤子里，身体肯定会乱动，站也不是，坐也不是。这个表达法一般在特别想做什么事情或者怀着焦虑或期望等待什么的场合使用。比如：

When the man who had promised to bring the money at lunch time hadn’t appeared by one-thirty, we all had ants in our pants.

那个人约定在午饭时间把钱拿来，等到一点半他还不见人影儿，我们大家都像热锅上的蚂蚁稳不住神了。

另外get pants in one’s pants也可表达相同的意思，比如：

Husbands often get ants in their pants while their wives are getting ready to go out.

当妻子在外出前久梳洗打扮的时候她们的丈夫总是等得不耐烦，坐立不安。

Let’s eat. The children are starting to get ants in their pants.

我们吃吧，孩子们已开始等得不耐烦，都坐不住了。

wear the pants in the family:

用通俗点的话就是“当家”。比如：

Most men make it very clear to their wives who wear pants in the family.

大多数男人都会向妻子明确家里谁当家。

如果自己认为已经说的很清楚，但是妻子却不听从，丈夫就要大喊大叫了：

I told you I wear the pants in the family.

我已经跟你讲过了，这个家我说的算，你别忘了这一点。

不过，最近下面的情况已经不足为奇：

Mrs. Smith seems to wear the pants in her family.

史密斯家似乎由太太当家。

另外需要注意的是在英式英语中要把pants改为trousers。

be caught with one’s pants down:

在口语中表示“措手不及，陷入囧境”。

She shouldn’t have entered the bedroom without knocking. I was caught with my pants down.

她不敲门就走进卧室，实在太不应该了。我还没来得及提裤子呢。

We hadn’t expected a test before finals so we were caught with our pants down when the professor gave us a pop quiz today.

我们没有想到在期末考试之前还会有考试，因此，今天老师搞突然袭击进行测验时，我们都被弄得措手不及。