单项选择
请认真阅读下面各题，从题中所给的A、B、C、D四个选项中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
21. What lessons China can draw from ______ global financial crisis has become _____ hot topic among us students.
A. a; the B. /; a C. the; a D. /; the
22.——Have you finished the book?
——No. I’ve read up to the children discover the secret cave.
A. which B. what C. that D. where
