Long before=很久以前
相对于过去,是过去的过去
long=很长一段时间
before=在······以前
long放在before前,
顺着词序理解
所以
long before
=比之前还要靠前的时间
=很久之前
例句:
I had seen the film long before.
很久之前我就看过那部电影了。
Before long=不久以后
很快
before=早于······(发生)
long=很长一个时间段
before放在long前面,
顺着词序理解
所以
before long
=早于很长一段时间(发生)
=很快要发生
=不久之后
例句:
She was glad. She could see her daughter before long.
她很开心,不久以后(很快)就能见到她的闺女了。