If you express your request as a conditional -- "if you could open the window, that would be great" -- even though the content is an imperative, the fact that you're not using the imperative voice means that you're not acting as if you're in a relationship of dominance, where you could presuppose the compliance of the other person.
倘若你用一个条件句表达请求： “您要是能开一下窗子就太好了，” 尽管内容是祈使句 仅仅因为你没有用祈使语态 就显示出你并没有按照一种支配的人际关系行事 你并没有假设他人必须服从