They____on the program for almost one month before l was arranged to help them. Now, we____on it as no result has come out.
#99542
A
had been working: are still working
B
had worked; were still working
C
have been working; have worked
D
have worked; are still working
推荐题目
Although the causes of cancer_____, we do not yet have any practical way to prevent it.
#104936
A
are being uncovered
B
have been uncovering
C
are uncovering
D
have uncovered
—Well, that was really a good meal. I _______ you were a really good cook.—Thank you.
#104832
A
didn’t know
B
don’t know
C
haven’t know
D
hadn’t known