Many provinces have been hit with smog. If _______ unsolved, the problem may lead to more serious results.
#80140
A
having left
B
to leave
C
left
D
leaving
推荐题目
It was only when I reread his poems recently ______ I began to appreciate their beauty.
#81867
A
that
B
until
C
then
D
so
about this computer program, a huge amount of time and energy .
#79940
A
Should I know; be saved
B
If I had known; can be saved
C
Had I known; would have been saved
D
Did I know; was saved
Just in front of our house _______ with a history of 1,000 years.
#79588
A
does a tall tree stand
B
stands a tall tree
C
is standing a tall tree
D
a tall tree stands
＿＿can you find out how many chickens there are!
#83918
A
Counting them
B
By counting them
C
Only by counting them
D
Only have you counted them
—________ one and a half months enough for the project to be finished?—I am afraid not. The professor is ill and only after he recovers ________ go on with it.
#79720
A
Is; he can
B
Are; he can
C
Is; can he
D
Are; can he