Every possible means ______ to prevent the air pollution, but the sky is still

题干

Every possible means ______ to prevent the air pollution, but the sky is still not clear.

A．has been used

B．have been used

C．is used

D．are used

上一题下一题 0.64难度单项选择更新时间:2014-07-08 10:21:29

小学学科试题库

初中学科试题库

高中学科试题库