We’ll have a holiday. What about going to the Great Wall?
A. three days
B. three-day
C. three-days
D. three-days’
网友回答
A. three days
(答案→)B. three-day
C. three-days
D. three-days’
解析：句意为我们将有一个三天的假期，去长城怎么样？三天的假期应表达为have a three-day holiday ，three-day 为复合形容词，连字符之间应用单数形式。所以选B 。