They were busy ________ an experiment when I came.
#92445
A
doing
B
to be doing
C
with doing
D
to do
推荐题目
We are going to talk about the problem _____ at the last meeting.
#94415
A
discussed
B
discussing
C
to discuss
D
being discussed
The next morning she found the man ___ in bed, dead.  
#88662
A
lying 
B
lie 
C
lay 
D
laying
Jack liked the milk so much that he had it ____to his house every week.
#90452
A
deliver
B
to deliver
C
delivered
D
delivering