I didn’t hear anyone shouting.I was ______(听) music then.

问题描述:

I didn’t hear anyone shouting.I was ______(听) music then.
listening
listen 不是不及物动词吗,后面怎么可以直接带宾语呢?我个人认为答案错了,想确认一下.我的答案是listening to .

listen后是必须加to