Li Ping likes music and she is good at ( ) 弹钢琴

问题描述:

Li Ping likes music and she is good at ( ) 弹钢琴
参考答案上说是 playing the piano ,但我认为是 plays the piano .
请说说谁对谁错,理由也请讲一下.

playing the piano 是对的.一个句子不可有两个凡是动词is 和plays