I often hear the lonely girl sing in her room

题目

I often hear the lonely girl sing in her room
为什么中间用sing而不用sings啊

答案

词组固定用法：hear sb.do/doing st.
1、经常听见某人做某事用do;
2、听见某人正在做某事用doing.
句中有“often”,说明是“经常”,因此要用动词原形sing,而不是sings(动词的单三形式）.
嘿嘿……