After_________walk，they all felt tired.
A.three hours B.three-hours
C.three hour’s D.three hours’
After_________walk，they all felt tired.
A.three hours B.three-hours
C.three hour’s D.three hours’
D
表时间的名词所有格用’s式，且以s结尾的复数名词所有格只加’，s省去。