Do you know we have much difficulty ____ the work on time.. 
#97766
A
on finishing
B
finishing
C
to finish
D
at finishing
推荐题目
Most computer users think it necessary for their software ________ regularly.
#89719
A
to up date
B
to be updated
C
to have been up dated
D
to have updated
___________ his poem, he didn’t dare to submit it to the professor.
#94509
A
Not having polished
B
Having not polished
C
Not polished
D
Not being polished