问题补充:
I think should be allowed to drive.
A. sixteen year old
B. sixteen-year-olds
C. sixteen years old
D. sixteens year old
答案:
A. sixteen year old
(答案→)B. sixteen-year-olds
C. sixteen years old
D. sixteens year old
解析:在此,sixteen-year-olds表示的16岁的人,符合题意。