strum on a piano

• 乱弹钢琴

strum on a piano的用法和样例：

例句

1. Peter is fooling around with the piano in his spare time.
   彼得总在业余时间乱弹钢琴。
2. Julie often likes thrumming on the piano instead of doing her formal practice.
   朱莉弹钢琴总喜欢随便乱弹而不做正规练习。