before ，after 和when 状语从句区别

Question

It won't be long _____we meet again in Beijing. A when Bwhile Cbefore Dafter

Answer 1

before 是指从句发生在主句之前，after是之后，when 表示同时

Answer 2

before在......之前 after在......之后 when当......时候

Answer 3

选C It won't be long before…意为“用不了多久就…” 原句的意思为“我们用不了多久就会在北京再见面的”