请问before的用法 据说有三个词性 请分别举例

prep.
1.在...以前
Only two days remained before the examination.
考前只剩下两天了.
2.(指顺序、重要性等)在...之前,先于
Your name comes before mine.
你的名字在我之前.
Pride comes before a fall.
骄必败.
3.由...考虑中
We will put the matter before the committee.
我将把此事提交委员会考虑.
4.在...前面;在...面前
She said she had never spoken before an audience.
她说她从未在大庭广众讲演过.
ad.
1.较早
Come at two o'clock,not before.
两点钟来,不必再早了.
2.以前;曾经
He was never late before.
过去他从不迟到.
Have you two met before?
你们两人以前见过面吗?
3.在前;向前
Several soldiers went before to scout.
数名士兵在前面探路.
conj.
1.在...以前
Check it carefully before you hand it in.
交来之前仔细核对一下.
2.与其...宁可
I'd die before I'd tell.
我宁死也决不会说出来.
3.否则,要不然
Get out before I call the police.
滚开,否则我叫警察.