______ their service, the workers of the hotel are active in learning English.
#91829
A
Improving
B
To improve
C
Improve
D
Having improved
推荐题目
The boy cheated in the English examination so he deserved ________.
#96103
A
being punished
B
to be punished
C
to punish
D
having punished
The graduation ceremony,_______ at 9 pm yesterday, was followed by a film .
#92885
A
starting
B
being started
C
to start
D
to be started
_____ to sunlight for too much time will do harm to one's skin. 
#98082
A
Exposed
B
Having exposed
C
Being exposed
D
After being exposed