一、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。
1. —______ useful information it is!
—I agree. It’s so important to us.
A. What an B. How C. How the D. What
2. — Do you know everyone from Class One?
— Er…, I know some of _______.
A. they B. their C. theirs D. them
