这些要素是基本信息，并且通常为你正在查看的内容做出解释。
These elements set the stage and usually explain what you are looking at.
测试电子邮件广告的要素包括：发送日期和时间、频率、个性化、主题和内容、价格和推广的行动。
Ideas for testing email campaigns include: sending day and time, frequency, personalization, subject and contents, prices, and call to action.
这些要素包括站内优化、网站内容、下载时间、重复内容和URL；以及站外优化，与可靠的目录、网站和地图建立链接。
These factors include on-page factors, content, download time, duplicate content and URL issues, and off-page factors such as securing links from credible directories, websites, and maps.
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