In strict doctypes, both of these require other blocklevelelements to be inside of them.
在strict文档类型定义里面，要求所有其他的块级元素都在它们里面。
2
This includes things like setting the margins on blocklevelelements like paragraphs, headers, and lists to the same value as (or some multiple of) the base line-height setting for the site.
这包括把类似p, header, li等块元素统一(或者部分分类)设置成站点的统一行高。
3
If the list item contains block-levelelements, then everything up to the first block is placed in the command; after that, any non-list items are placed in an wrapper.