－Where did you go the morning of April 6?－I didn’t come to the office the meeting was ov

问题补充：

－Where did you go the morning of April 6?

－I didn’t come to the office the meeting was over.

A. in, when

B. at, unless

C. on, until

D. to, though

答案：

A. in, when

B. at, unless

(答案→)C. on, until

D. to, though

解析：确指某天的上午、下午或晚上时要用介词on not…until固定结构。