第二部分 英语知识运用(共两节，满分35分)
第一节 语法和词汇知识(共15小题，每小题1分，满分15分)
21. I was halfway back to the hospital where the doctor was working ______Susan caught up with me.
A. when B. while C. until D. though
22. —John, how did your English exam go？
—I thought I ________have failed, but in fact I came in the top 10 in the class.
A. should B. couldn’t C. might D. mustn’t
