一、单项选择题(共20小题,每小题1分,满分20分) 从A、B、C、D四个选项中,选出可以填入空白的最佳选项。 1. I remember Susan left _______ a very cold morning of January. A. in B. on C. at D. from 2. It was raining hard, they _______ stay at home. A. must B. would C. had to D. could 3. Hurry up! The play _______ for ten minutes. A. has begun B. had begun C. has been on D. began