She will tell everybody that each of us has a role .in making the river and air clean.

题目

She will tell everybody that each of us has a role .in making the river and air clean.
虚线处应该选哪一个,为什么?
A to be playing B to have played C to be played D to play

答案

选D,短语to play a role in 表示起什么作用,这里的to play做后置定语,修饰role