第一节单选填空（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，并在答题卡上将该选项涂黑。
21. ——I don’t think I’ll be able to go mountain-climbing with you tomorrow.
——______?
A. So what B. How come C. I don’t mind D. It depends
22. Due to the widespread________ of this medical technology, more diseases can be discovered and treated at an early stage.
A. argument B. application C. explanation D. distinction
23. Ladex doesn’t feel like abroad. Her parents are old.
A. studying B. study C. studied D. to study
24. Henry as well as Tom and James ______________ for the loss.
A. are to blamed B. is to blamed C. is to blame D. are to blame
