二、知识运用(共两节, 满分45分)
第一节:单项填空(共15小题,每小题1分,满分15分)
从每题所给的A、B、C、D四个选项中,选出可以填入空白处的最佳选项。
21.Besides the others, there was still      third one who said he was        second to reach the end.
       A.a; a                     B.a; the                  C.the; the               D.the; a
22.The purpose of their explorations is as important to them as       to us.
       A.they are              B.they have            C.it is                     D.it has