the morning of the second day of the meeting Dr. Smith read his paper.A. AtB. InC. OnD. F

问题补充：

the morning of the second day of the meeting, Dr. Smith read his paper.

A. At

B. In

C. On

D. From

答案：

A. At

B. In

(答案→)C. On

D. From

解析：考查介词用法。在特定的某一天的上下午用on;句意：在会议第二天的早晨，Dr. Smith读了他的论文。