Question

An ______ boy came to our class yesterday.

1. A.
   11-year-old
2. B.
   11-years-old
3. C.
   11-year old
4. D.
   11 years old

Answer 1

A
修饰名词的年龄，应用连字符将它们连在一起，用连字符连在一起的单词不可使用复数，故本题选A。