佛山市

before long与long before
  before long是soon或a little later的意思，即：“很快”，“不久”。before是介词，long在这里是名词。如：
  (1) It looks a bit large．看来大了一点。
  (2) I think it'll fit me quite well before long, Mum.
  妈妈，我想（这件大衣）很快就会合身的。
  (2) Marxmade such rapid progress that
  before long he began to write articles for an American newspaper.
  马克思进步很快，不久就开始（用英语）给美国一家报纸写文章。
  long before是a long time earlier的意思，即：“很久以前”。long和before在这里都是副词。如：
  (1) That happened long before.
  那是很久以前发生的事。！
  (2) He said he had seen the film long before.
  他说他很久以前看过这电影。
  ·石零·