While watching television, __________.
#90451
A
the doorbell rang
B
the doorbell rings
C
we heard the doorbell ring
D
we heard the doorbell rings
推荐题目
. Mr. Green requires that the students ______ cheat in any exam.
#88188
A
should
B
don’t
C
wouldn’t
D
not
Without your help, I ____the exam last term. 
#89943
A
failed in
B
would have failed
C
wouldn’t pass
D
would fail
This vase ________ perfect but for a few small holes in its base.
#86632
A
would have been 
B
should have been
C
shall be 
D
would be
I_______  such a foolish mistake if I had been a little more careful.
#87484
A
wouldn’t make
B
wouldn’t have made
C
hadn’t made
D
didn’t make