快速答案
acontecer 是日常的“发生”；ocorrer 更正式，常见于报告。
可靠的方法是先判断这个词在句子里的功能，再翻译。
每个词的作用
acontecer
to happen
Use acontecer for events and situations in ordinary conversation.
ocorrer
to occur
Use ocorrer for events in neutral, formal, journalistic, or technical language.
如何选择
- acontecer: Choose acontecer if the sentence points to events and situations in ordinary conversation.
- ocorrer: Choose ocorrer if the sentence points to events in neutral, formal, journalistic, or technical language.
例句
O que aconteceu ontem?
What happened yesterday?
O acidente ocorreu de madrugada.
The accident occurred before dawn.
常见误区
Ocorrer also has a separate use meaning “come to mind”: ocorreu-me uma ideia. Acontecer cannot replace it there.
放到语境中练习
从你的真实生活中选一个句子，写两遍：一次用 acontecer，一次用 ocorrer。如果两个版本都可以，说明意思怎样变化。