he is the only one of the students in our school who plys the piano well.

问题描述:

he is the only one of the students in our school who plys the piano well.

这句话不对.本句who plays the piano well 中的plays 拼写错了.而且此从句的先行词应为one ,当先行词前有the only ,the very ,the last 等修饰时,关系代词只能用that.因此本句中的关系代词应用that.