Every possible means ___ to prevent the air pollution, but the sky is still not clear．
#101596
A
is used
B
are used
C
has been used
D
have been used
推荐题目
---- Do you live in this city?---- No, we ______ it for holidays.
#104108
A
just visit
B
just visited
C
are just visiting
D
have visited
---- Are we going sightseeing next week?---- No. The plan ________ at the second meeting.
#102175
A
had cancelled
B
was cancelled
C
has been cancelled
D
would cancel
—That must have been a lot of work.—Yeah, it us three days to finish it.
#100767
A
takes
B
had taken
C
took
D
was taking
--- I’m sure Andrew will win the first prize in the final.--- I think so. He ___________ for it for months
#104866
A
is preparing
B
was preparing
C
had been preparing
D
has been preparing