I visited my grandparents _ A.on my three days off B.on my three-day off

问题描述:

I visited my grandparents _ A.on my three days off B.on my three-day off

B.on my three-day off
【速度回答,希望已帮您解惑,有疑问请再问!】选B的原因是什么呢?我说习惯用法是不是有点牵强?选B肯定是没错的,具体怎么解释,我有点词穷。。。谢谢你!