在遇见before和until表“在……之前”含义时解析区别，许多英语大家都是含混不清，说法错漏百出，今天手痒我就免费为同学们秒*了这个难点：
1. before和until都可以表示主句的情景发生在从句之前：
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。
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。
We need more time to see how things develop before we take action.
我们采取行动以前需要有更多时间观察情况的发展。
Some children can read and write before they go to school.
有些孩子在上学前就会看书写字了。
Until she spoke I hadn't realized she wasn't English.
直到她开口说话我才知道她不是英格兰人。
You're not going out until you've finished this.
你不把这事做完就不准出去。
The EU will not lift its sanctions until that country makes political changes.
除非该国实施政治改革，否则欧盟将不会解除制裁。
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。
I won't go until I'm good and ready.
我要完全准备就绪后才走。
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。
Things were going fine until you showed up.
你一露面就把事情搞糟了。
She wanted to continue working until she was 60.
她想要继续工作到60岁。
2. before表“在……之前”用法广泛，主句可以是肯定句或否定句、主句谓语动词可以是瞬间或非瞬间动词（持续性动词）；而until表“在……之前”时，其主句如为肯定句时，其谓语动词必须是非瞬间动词（持续性动词）：
I hadn’t waited long before he came.
我没有等等长时间他就来了。
He applied three times before he was finally admitted to the university.
他申请了三次大学入学，最后才被大学录取。
Someone called me up in the middle of the night, but they hung up before I could answer the phone.
有人半夜给我打电话，但我还没来得及接电话，他们就挂了。
I waited until he returned..我一直等到他回来。
Can you last until I can get help?
你能支撑到有人来帮我吗？
I waited until it got dark.
我一直等到天黑。
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.before引出的从句内容的真实性或非真实均可；until引出的从句内容一般是真实的：
And before she could speak again I began to talk.
她尚未再开口，我就开始说话了。
Pigs will fly before he’ll become a mathematician.
她要是能当数学家，诸都会飞了。
I will try to finish this work before you can come.
我会尽力在你来之前完成这项工作。
Until she spoke I hadn't realized she wasn't English.
直到她开口说话我才知道她不是英格兰人。
Let’s wait until the rain stops.
让我们等到雨停吧。
According to scientists, dinosaurs dominated the earth for 150 million years until they suddenly vanished 65 million years age.
据科学家称，恐龙统治地球1.5亿年，直到6500万年前突然消失。
