" Until" specifies a certain period of time when something can (or cannot) happen unless something else happens.

“Until”指定某段时间，除非发生其他事情，否则某些事情可以（或不能）发生。

It's a somewhat of a poetical way of describing a certain period of time during the first part of the day.

在一天的第一部分，这是一种描述特定时间段的诗意方式。