before和until的区别
一、读音不同
before 英[bɪˈfɔː(r)] 美[bɪˈfɔːr]
until 英[ənˈtɪl] 美[ənˈtɪl]
二、释义不同
before
prep. 之前; 在…以前; 在…面前(或前面); (次序或排列)在前面; 当面;
conj. 在…以前; 到…为止; 到…之前; 以免; 不然; （宁可…而）不愿;
adv. 以前; 过去; 已经;
until
conj./prep.直到; 到…时; 直到…为止;
三、用法不同
until 意为“到……为止”，before意为“在……之前”
①如果主句（或简单句）中的谓语动词为非延续性动词的肯定式，只能用before，不可用until。如：
He can come here before sunset. 在日落之前他能来这。
② 如果主句（或简单句）中的谓语动词为延续性动词的否定式，多用before，一般不用until。如：
He has not done anything before she comes. 在她来之前，他什么也没做。
③ 在It wasn't until ... that 强调结构中不用before。如：
It wasn't until this morning that I heard the news. 直到今天早上我才听到这个消息。
五、双语例句
before
1、Test the heat of the water before getting in.
入水之前先试一试水温。
2、It would be a good idea to call before we leave.
我们出发之前打个电话是个好主意。
3、It was many years before the full story was made public.
许多年之后，事情的全貌才公之于众。
4、I'd like a second opinion before I make a decision.
我在作决定之前，想听听别人的意见。
5、I didn't have time to change clothes before the party.
我没时间在聚会前更换衣服。
until
1、We didn't leave until the very end.
我们直到最后才离开。
2、We will explore every avenue until we find an answer.
我们要探索一切途径，直到找到答案为止。
3、Can you last until I can get help?
你能支撑到有人来帮我吗？
4、I won't go until I'm good and ready.
我要完全准备就绪后才走。
5、By law, you are a child until you are 18.
按照法律规定，18岁之前是未成年人。