第一节：单项填空（共15小题；每小题1分，满分15分）
从A、B、C、D四个选项中，选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。
21. Each member of ______ Green Peace Club is required to gain _____ better understanding of their system.
A. the; the B. the; a C. /; a D. /; /
22. Alice cares most about her clothing, who is followed by Mary, while Della shows _____ interest in fashion.
A. more B. the most C. less D. the least