问题补充：
—What do you plan to do on the May Day holiday?
—I have no idea. Probably, I will spend it by doing many papers.
A. three-day
B. three-days
C. three days
D. three day’s
答案：
(答案→)A. three-day
B. three-days
C. three days
D. three day’s
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:在三天的五一假期中，你计划做点什么？——我不直到。可能，我会做很多份试题。结合语境可知本句中合成词用作符合形容词，作定语，故选A。
