请问occur 和happen有什么区别

请问occur 和happen有什么区别 英语单词：happen与occur有什么区别? occur to和happen to的区别我们常见:It happen to sb.那么,It occur to sb和上面的那句有什么区别呢?请具体给我occur和happen的用法 occur,take place,happen,break out有什么区别? Occur与happen有何区别? occur happen的区别 occur和happen到底有什么区别啊?老师说sth occur to sb是某人发生了某事,又说it occur to sb是某人突然想到某事,还是分不清, occur的用法?和happen.take place 的区别 happen on 和 happen to 有什么区别正确. occur,happen,take place,hold的区别请问这些短语的区别 happen,take place与occur 的区别 happen与occur的区别是什么? occur与happen的区别是什么? occur to /happen toit occur to sb.to do sth ...与it occur to sb that从句..有何区别..it happen to do sth 与it happen to that 从句..有何区别 occur和happen的差别在哪里 帮忙辨析几个词组：occur take place happen有什么异同?字典说：occur可以指偶然的事件,happen也可以.晕过去了、 what has happen 和what was happen 和what happen有什么区别,它们后面都能加to吗? what happen和what happened有什么区别