The best way to prevent the air polluting _____ , but the sky is still not clear.
#102116
A
is used
B
are used
C
has been used
D
have been used
推荐题目
Now then, children, it’s right time you ______.
#102530
A
wash and dress
B
are washed and dressed
C
will wash and dress
D
were washed and dressed
Because the shop ______, all the T-shirts are sold at half price.
#101466
A
has closed down
B
closed down
C
is closing down
D
had closed down