catch sb doing it是什么意思

catch sb doing it
撞见某人干某事/当场抓住

I'll tan your hide if I catch you doing it again.
要是我再撞见你干那种事情，我就要打你一顿了。

I suspect Terry has been pilfering goods from the stores. Give him enough rope, and we'll catch him doing it one day.
我怀疑特里一直在偷商店里的东西。暂时不管他，总有一天我们会当场抓住他的

发现某人在做那件事。

catch做发现或发觉（某人在做某事）解

刚好碰上某人在做某事
或者是刚好撞见某人在做某事

楼上回答正确。

看到某人正在做某做

同意