a 20 minutes' walk和 a 20-minute walk 有什么不同?
问题描述：
a 20 minutes' walk和 a 20-minute walk 有什么不同?
1.every morning Mr.Smith takes a ________to his office.
A.20minutes' walk B.20minute's walk C.20minutes walk D.20-minute walk
这里选D 为什么不能选A呢
2.My home is about ______from my school.
A.15 minutes B.10-minute ride C.20 minutes' by bike D.15-minute's on foot
这里选B 为什么前面不加a呢?
答
1是做宾语,这种中心位置,如主语,表语,宾语,要加A
2这是定语,不用加.
就这么简单.