如果由数据过期来管理刷新，就像Web页面情况一样，那么可以使用策略或策略集合内部的关键字，来通知任意的缓存，告诉他们数据可以保持多长时间的方式来实现。

If refresh is managed by data expiration, as is the case for Web pages, it can be implemented using keywords inside policies or policy sets to inform any caches how long they can retain the data.

youdao

YouTube API还允许开发人员根据关键字搜索视频，使用与类别相似的方式。

And the YouTube API allows developers to search for videos by keyword, in a manner similar to that used for categories.

youdao

你可以使用便于记忆的关键字来为这些网站提供快捷的访问方式。

You can make short keywords that you will remember to provide quick access to the sites.

youdao