问题补充：
The market isn’t far from here. It’s only bicycle ride.
A. half an hours’
B. half an hour’s
C. half an hour
D. an hour and a half
答案：
A. half an hours’
(答案→)B. half an hour’s
C. half an hour
D. an hour and a half
解析：根据句意下文应是说仅仅骑自行车半小时的路程，表示词组的所有格时只要在词组最后一个单词后面加’s，half an hour是单数后面不加s，所以选B.
