问题描述：
it won't be very long before .句型用法 it will be +段时间+before .句型用法
问题解答：
我来补答
it won't be very long before + 句子（谓语动词用一般现在时）
如：It won't be long before I return to Beijing
翻译：我很快就要回北京了
It will be two weeks before she comes here.
翻译：过两周她就来了.
How long will it be before we meet
翻译：我们过多久见面?
再问： 此否定结构能否把before 换为until?
再答： 你好。不可以，因为它们之间不存在互换关系。 It won't be long before I return to Beijing------ It won't be long until I return to Beijing.(是错句)，但这一句是对的：I won't return to Beijing until Monday / - - ---until next week. / -- -- - until five days from today.
