Why not go swimming with me this evening?I'm so tired after____work,so I have to have a good rest.

问题描述:

Why not go swimming with me this evening?I'm so tired after____work,so I have to have a good rest.
A.four hours'
B.four hours
C.four hour's
D.fourth hours'

A.four hours'这么快O__O"…解释一下习惯用法四个小时用复数然后那一撇要在s后面