从A、B、C、D四个选项中，选出可以填人空白处的最佳选项，并在答题卡上将该项涂黑。
21.It is ______great pleasure to meet the expert who is doing research on ______archaeology..
A./ ; / B./ ;the C. a ;the D. a ; /
22.We should be a _______a lot of animals are becoming endangered.
A. preserved that B. aware of C. aware that D. sure that
23.His bad manners _______a lack of family education.
A.insist B.want C.suppose D.suggest
