I'm going to learn play an instrument.learn后为什么不加to?

I'm going to learn play an instrument.learn后为什么不加to? 1.I'm going to learn to (l ) to play an instrument.2.I'm goi Do you want to learn to play an instrument?play前为什么要加to? 八上英语词首字母填空I'm going to learn to p______ an instrument I'm going to learn how to I'm going to learn huangfu 几个英语问题1.I"m going to learn to play the piano after I retire- i'm going to learn how to back a l'm going to learn to swim i want to learn to swim为什么加to I'm going to learn english这句话对吗? i'm going to learn _second language in _second grade