listen/listen for/listen in的用法（比如后面能接什么）

我把LONGMAN的解释给楼主看看， 参考一下吧
listen for: to pay attention so that you are sure you will hear a sound
listen in: A. to listen to a broastcast on the radio; B. to listen to someone's conversation without them knowing it
listen out: to listen carefully, especially for an unexpected sound
listen up: used to get people's attention so they can hear what you are going to say

listen -- 除了for/in,还可以接to
listen for -- 留意地倾听,例
I listened for his footsteps.我倾听以便觉察他的脚步声.
listen in -- 外来者加入对话型的听,例：
I'm not taking the class,but can I listen in?我没修这门课,但是可以来旁听吗?