happen
单词辨析：
普通用词，多用于偶然事件。
The accident happened at 5 o'clock.
事故发生在5点钟。
What happened then?
后来又发生了什么事？
可用于偶然事件或计划之事，可与 happen 换用。
The earthquake occurred/happened at dawn.
地震发生在黎明时分。
A serious traffic accident occurred/happened yesterday.
昨天发生了一起严重的交通事故。
主要用于事先计划好的事情。
Great changes have taken place in China.
中国发生了翻天覆地的变化。
The parade will take place on Sunday, rain or shine.
庆祝游行定于星期日举行，风雨无阻。
相关例句：
If we had been spotted at that point, I don't know what would have happened to us
如果当时我们被发现了，我不知道会有什么后果。
There's no sense in pretending this doesn't happen
假装这件事没有发生毫无意义。
What if anything should happen to the child?
万一这孩子出了差错怎么办？
Just when this will happen is anyone's guess
谁也说不准这事什么时候会发生。
It's the best thing that ever happened to me.
这是我所遇到的最好的事情了。
I looked in the nearest paper, which happened to be the Daily Mail
我仔细看了一下离自己最近的那份报纸，正巧是份《每日邮报》。