第一节 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。
21. John has tried many ways to solve the physics problems, but _______ works.
A. neither B. no one C. none D. nothing
22. —I’m sorry. I shouldn’t have been rude to you.
—You _______ your temper but that’s all right.
A. have lost B. had lost C. were losing D. did lose
23. It’s quite natural that kids like to play with friends _______ their own age.
A. of B. at C. with D. in
