When first __________ to the market, the computer software was not a success due to its complexity in operation. 
#96476
A
introducing
B
being introduced
C
introduced
D
to be introduced
推荐题目
It’s time he _________ piano. Don’t you think he has wasted too much time online? 
#96148
A
stopped to take up
B
stops taking up
C
stopped to leave alone
D
stops leaving alone
The mother didn't know who ________ for the broken glass as it happened.
#91561
A
to blame
B
to be blamed
C
blamed
D
is to be blamed