He had to jump over the _____ wall to fetch the ball.

题目

He had to jump over the _____ wall to fetch the ball.
A.six foots high B.six feet high C.six--foot--high D.six--feet--high 选哪一个啊?为什么啊

答案

选C 复合形容词中名词不用复数.如：a seven-year -old boy ,1ooo-metre race