time to catch one's breath 喘口气的功夫

I don't even have time to catch my breath.
我连喘口气的工夫都没有。

irons in the fire 要做的事情

Don't have too many irons in the fire.
不要揽事太多。

in the middle of something 正忙于某事

I'm in the middle of something. Could you call back later?
我现在很忙，你能过会给我打电话吗？

be tied up 被占用，很忙

I'll be tied up the rest of the week, I am afraid.
这个星期我恐怕都抽不出时间。

busy as a beaver 忙得团团转

He is working so hard that he is as busy as a beaver.
他没日没夜地工作，看起来很忙。

be as busy as a bee 忙忙碌碌，忙死忙活的

He was as busy as a bee trying to put the house in order.
他为了要把家里弄得整整齐齐，忙了好一阵子。

a million things 很多很多事情

It's hard to slow down when you are trying to do a million things.
当你想要干成百上千件事情的时候是很难慢下来的。

be up to one's neck 忙得不可开交

I can't possibly come out tonight, I'm up to my neck in work.
今晚我不可能出来，我的工作忙得不可开交。

have/get one's hands full 很忙，应接不暇

Three emergency cases came into the hospital at the same time and the doctors really had their hands full.
三个急诊病人被同时送到医院，医生们真是应接不暇。