—Is there any possible way to help them get rid of such a bad habit?—To tell the truth, it’s very hard. But we ________ on this problem, trying to improve the situation .
#101218
A
worked
B
had worked
C
are working
D
had been working
推荐题目
The professor walked onto the platform and seated himself in a chair, ____ for answering questions.
#104211
A
had prepared
B
being prepared
C
preparing
D
prepared
During the past 120 years, the world three waves of global economic integration（联合）.
#100672
A
witnessed
B
witnesses
C
has witnessed
D
will witness
He _____ on the bench, with his head down and his eyes _____ on the ground.
#103111
A
was seated; fixing
B
was seated; fixed
C
seated; fixing
D
seating; fixed
In the past twenty years great changes _______in China.
#103431
A
were taken place
B
have been taken place
C
have taken place
D
were happened