问题补充：
The Wangs will have holiday in America.
A. three weeks
B. three week
C. three-week
D. a three-week
答案：
A. three weeks
B. three week
C. three-week
(答案→)D. a three-week
解析：英语中两个或多个单词中间可以用短横线连接起来，起一个相当于形容词的作用，这类单词叫做合成词。其一般构成规则就是其构成单词一般都要用原形。句意:王姓一家要去美国度一个为期三天的假期。结合语境可知本句为合成词做定语。故选D。
