第二部分:英语知识运用(共两节,满分45分)
第一节:语法和词汇知识(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. Unfortunately, when I dropped in, Doctor Li _____ for Beijing to join in the fight against SARS, so we had not enough time for a talk.
A. just left B. has just left C. is just leaving D. was just leaving