问:变成否定句:I used to play the piano.答:1) I _____ to play the piano.2) I didn't use to play the piano.第二个我会做,请问第一个应该填什么呢?

问题描述:

问:变成否定句:I used to play the piano.
答:1) I _____ to play the piano.
2) I didn't use to play the piano.
第二个我会做,请问第一个应该填什么呢?