In order to attend, you must know the date and the time. You can ask your friend, "When is your wedding?"

为了能够出席，你必须知道具体的日期和时间，你可以问你的朋友，“When is your wedding？”

When 课堂 - SpeakingMax英语口语达人

They had a certain time and date when the world was going to end.

他们相信在某个时间某个地点,世界末日就会出现。

耶鲁公开课 - 心理学导论课程节选