Jane is high school student in the United States.A. an 18-year-old B. a 18-years-old C. an

问题补充：

Jane is high school student in the United States.

A. an 18-year-old

B. a 18-years-old

C. an 18-years-old

D. a 18-year-old

答案：

(答案→)A. an 18-year-old

B. a 18-years-old

C. an 18-years-old

D. a 18-year-old

解析：句意：Jane是一个18岁的美国高中生。18-year-old 18岁，做定语，修饰后面的名词，注意有连字符时year不用复数；单词eighteen读音以元音开头，所以前面用冠词an，故选A。