you should never open a door___going to see who it is我想填before但答案时without可不可解释下

without：
一、基本用法
1.(表否定)没有,无,不需.
2.(用在no,not,never等否定副词之后,强调肯定)没有……不,没有……则不能……,每……必定…….
3.(与-ing形式连用)不,无,没.
4.(表条件)若无,若非.
二、作表语的用法
without引出的介词短语通常用作状语,但有时也可用作表语.如：
She is completely without shame.她恬不知耻.
My investigations were without result.我的调查毫无结果.
The houses in this village are without water.这个村子里家家户户都没有自来水.
We were without electricity for three hours but it’s on again now.我们的电停了3小时,现在又有了.
三、后接复合宾语的用法
without后接复合宾语的常用结构如下：
1.without+宾语+副词
I’d be lost without you here.没有你在这儿,我会一筹莫展.
I’m very near-sighted without my glasses on.我要是不戴眼镜十分近视.
2.without+宾语+介词短语
We’d be better off without them as neighbors.要是没有这些邻居,我们就过得更愉快了.
I don’t like sweet coffee; I like it better without sugar in it.我不喜欢加糖的咖啡,里边不加糖我更喜欢.
3.without+宾语+动名词
Without anyone noticing,he slipped through the window.无人注意,他从窗户溜了出去.
They debated for hours without a decision being taken.他们争论了几个小时,也没作出决定.
4.without+宾语+不定式
Without anyone to help,how can we go on?没有人帮忙,我们怎么能进行下去?
It was boring to sit there without anything to do.无所事事地坐在那里太无聊了.
5.without+宾语+过去分词
Without another word exchanged,they started off.没有再交谈一句,他们就出发了.
这样你应该明白了吧!before？