Every possible means to prevent the air pollution, but the sky is not still clear.
#101886
A
is used
B
are used
C
has been used
D
have been used
推荐题目
The film _______ for twenty minutes when they got to the cinema．
#103330
A
had already been on
B
has already been on
C
had already begun
D
has already begun
He is the only one of the students who _____ a winner of scholarship for three years.
#102115
A
is
B
are
C
have been
D
has been
— Lucy, how are you getting on with your composition?— I have rewritten it so many times that I wonder if I ________ it.
#99786
A
finish
B
finished
C
have finished
D
will finish
—What do you think Mr.Green is like?—Haven’t you seen through him?I have warned you again and again that men of this kind______
#103614
A
is in danger
B
are in danger
C
is dangerous
D
are dangerous