21..-----What do you think of ____concert last night?
---No doubt it was ____great success.
A.a ; the B. the ; a C. the ; 不填 D. a; 不填
22.It can not be a(n) ___that four jewellery stores were robbed in one night.
A.coincidence B. accident C. incident D. chance
23.They will start their project ____at helping the poor children to be educated in China＇s west.
A .aims B. aiming C. being aimed D. aimed
