知识运用 （共27分）
四、单项填空 （共15分，每小题1分）
从下面各题所给的A、B、C、D四个选项中，选择可以填入空白处的最佳选项。
21. --- Who is the woman in black?
--- ________ is our physics teacher.
A. She B. Her C. Hers D. Herself
22. The school bus picks up the students ________ the morning.
A. by B. to C. on D. in
