1. Before + 名词/代词/动词的-ing形式，表示在某事之前发生的动作或状态。
例如：
Before leaving home, she always checks that she has her keys.
走之前，她总是检查她有没有带钥匙。
He had never seen the sea before.
他以前从没有见过大海。
2. Before + 句子，表示在某事发生之前的情况。
例如：
I need to finish this report before I leave for the weekend.
我需要在周末离开之前完成这份报告。
She wanted to talk to her boss before he left the office.
她想在老板离开办公室之前和他谈谈。
3. Before + 现在完成时，表示完成某事前已经做了某个动作。
例如：
I have never seen such a beautiful sunset before.
我以前从未看过如此美丽的日落。
She has already finished her work before her colleagues arrived.
她在同事到达前已经完成了工作。
4. Before + 过去完成时，表示完成某事以前已经做了某个动作。
例如：
He had studied hard before he took the exam.
他参加考试前已经努力学习了。
They had already eaten dinner before they went to the cinema.
对于这个问题，我还需要更多的上下文和信息才能回答。您可以给我更多的细节和背景吗？需要帮助的是什么？谢谢！
(1) before sb can/ could … 某人还没来得及……
例：Before I could get in a word ，he had measured me.
我还没来得及插话，他就给我量好了尺寸。
(2) It will be +时间+ before +从句； 还有多长时间……
例：It will be 4 years before he graduates.
他还有四年时间变毕业了。
(3) had done some time before (才……)
例：We had sailed four days and four nights before we saw land.
我们航行了四天四夜才见到陆地。
(4) had not done ... before ... 不到……就……
例：We hadn’t run a mile before he felt tired.
我们还没走到一英里路就觉得累了。
区别就是两者动词形式是不一样具体的不同如下
begins为动词第三人称单数形式中文意思是v.
词典
begin的第三人称单数;
A typical working day for me begins at 7.30.
我的工作日一般在7:30开始。
begin为动词原形中文意思是v.