There's another advanced class today at four o'clock.
今天下午四点钟还有一次高级班。
I've forgotten what time he said he had dinner last night.
我忘记了他昨晚什么时间吃晚饭的了。
If you want to send a letter to an office abroad that is in a different time zone, you can send a fax, and it will be received even though the office is not open.