Admittedly, this property is a confusing one because it reads like a double negative, but by default, all read and unread documents are tracked in a database.

• 大家都认为这条属性令人费解,因为它读起来像是一个双重否定句,但是在默认情况下,数据库中所有已读的和未读的文档都会被跟踪。