We omitted some optional fields for simplicity.
为了简单起见，我们省略了一些可选域。
The article wraps up with some optional features you can use to further streamline this process.
本文最后将给出一些可以用于进一步简化此流程的可选功能。
Why couldn't we add a simple mechanism to PubSubHub so that when a client subscribes to push updates, it leaves behind some optional identifying information about the user like their name and avatar?
我们为什么不给PSHB协议添加一种简单机制，当客户端订阅推送更新时会留下一些识别信息，如姓名、头像等？
There are also some optional textbooks and recommended Web material. And there will be some additional material handed out in class.
另外还有一些推荐的教材和网上资料，在课堂上还会分发一些补充材料。
Of course, if some optional information is missing from the HTML document, the associate fields will be left blank, but this is not uncommon in any database.
当然，如果某些任选信息在HTML文档中缺失，有关字段就留作空白，但这种情况在任何数据库中都是常见的。
Some optional items that I found useful are as follows.
一些可选项目，我发现有用的内容如下。
Some optional items that I found useful are as follows.
一些可选项目，我发现有用的内容如下。
应用推荐