题目内容
Trees ____ fight air pollution．They are natural air conditioners．
A．should B．must C．need D．can
试题答案
1、D
相关题目
Trees ____ fight air pollution．They are natural air conditioners．
A．should B．must C．need D．can
查看习题详情和答案>>
Trees ____ fight air pollution．They are natural air conditioners．
A．should B．must C．need D．can
查看习题详情和答案>>