before prep. adv. conj
在之前;在前;以前;
短语：1.before long 不久以后：
e.g. Before long ,news came that China lost the game.
不久以后传来消息说中国队比赛输了。
2.the day before yesterday ：
e.g. He went to see his grandmother the day before yesterday.
他前天去看望他奶奶了。
3.long before 很久以前。
e.g.She said she had seen the film long before.她说很久以前就看过这部电影。