The lecture begins at 9 tomorrow morning .So I have to be at the hall 8:40 pm. at the late

问题补充：

The lecture begins at 9 tomorrow morning .So I have to be at the hall 8:40 pm. at the latest.

A untilB afterC byD around

答案：

解析：by 后面加时间表示：到这时间为止。