_________ the floor, I found his pen lying on the ground. 
#82531
A
While sweeping
B
While swept
C
If sweeping
D
If swept
推荐题目
Only that factory ____________ yesterday __________ this kind of machines.
#81190
A
we visited; produces
B
did visited; does it produce
C
we visited; does it produce
D
did we visit; produce
________ entered the classroom _________ the bell rang.
#82655
A
We hardly had, before
B
Hardly had we, when
C
Hardly had we, than
D
Hardly did we, when
Not until the 11th century, when a young lady brought a fork to Italy, _______.
#81865
A
and the custom reached Europe.
B
that the custom reached Europe.
C
did the custom reach Europe.
D
so did the custom reach Europe.
Only after they had carried out over ten experiments ______ the decision.
#82493
A
they reached
B
they reach
C
did they reach
D
do they reach