第二部分 语法和词汇知识（每小题1分，共25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. Unfortunately, the poor boy had no money _____ he could buy a train ticket.
A. by which B. on which C. with which D. for which
22. The students read English aloud every morning, ______is helpful to them.
A. it B. which C. that D. what
23. Tell us everything ______you know about the accident.
A. which B. about that C. about which D. that
24. Who ____has common sense will do such a silly thing?
A. which B. who C. whom D. that
