Every possible means _____ to prevent th
题型:选择题
问题:
Every possible means _____ to prevent the air pollution, but the sky is still not clear.
A.is used
B.are used
C.has been used
D.have been used
Every possible means _____ to prevent the air pollution, but the sky is still not clear.
A.is used
B.are used
C.has been used
D.have been used