看欧美电影不可不知的口语

on to 识破意图  = to know what someone doing

After months of detective work, the police were finally on to the plans of the criminals.  在几个月的侦查工作以后,警察最终识破了罪犯的意图.

I want to keep the birthday present a secret but I think she is on to me. 我本来打算对生日礼物保密的,但是还是被她识破了.