Once environment damage___, it takes many years for the system to recover（）
A. is done
B. does
C. is doing
D. did
The work_by the time you get there（）
A. has been done
B. had been done
C. will have been done
D. will be done
I am ______ of his honesty（）
A. convincing
B. convinced
C. convince
D. to convince
Before announcing the next day’s schedule, who should the local guide consult with first（）
A. the oldest guests
B. the driver
C. the national guide and the group leader
D. all the guests
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