第二部分：英语知识运用(共两节，满分45分)
第一节 单项选择(共15小题；每题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．—Since you can't find a better way out for the time being，why not follow his advice?
—Oh，_____________．
A.I believe not B．I might as well C．It doesn't matter D．I don't care