第一节 单项填空（共15小题；每小题重分，满分15分）
21．The earthquake in Sichuan and the result ________ brings have great influence on the people there．
A．which B．it C．that D．what
22．They ________ on the program for almost one week before I joined them, and now we ________ on it as no good results have come out so far．
A．had been working; are still working B．had worked; were still working
C．have been working; have worked D．have worked; are still working
