overhearing

动词 overhear:

1. hear, usually without the knowledge of the speakers
   同义词：catch, take in, overhear

1. He dropped his voice for fear be might be overheard.
   他放低了声音，唯恐被别人听见。
2. I can not help overhearing ...
   我无意中听到你们的谈话 ...