happen to do的相关用法问题she happened to have heard the news她碰巧听到了这个消息 和 she happened to hear the news 有什么区别

问个关于happen的用法的问题.happen.不是happen to do sth.那么 碰巧去做,碰巧正做,和碰巧已做.是不是分别是happen to do,happen to doing,happen to have been? happen to 的用法 happen to do的相关用法问题she happened to have heard the news她碰巧听到了这个消息 和 she happened to hear the news 有什么区别 happen 有 sth happen to sb或者sb happen to do sth 那么occur同样的用法吗? happen to do sth happen的各种形式及用法 与其有关的常用短语 it's +形容词+to do的用法 happen to的用法happen to to 为介词时的用法. 请教这个句子.do you happen to know if she left a message?do you happen to know if she left a message?有点难理解这句话,happen to的用法求指教. happen用法what's happened to you What's happened toyou what happen to you what's happened to you happen to do sth的汉语是什么? happen的用法 happen 的用法 happen的用法. 求what happen to...用法 happen to do or happen doing? 到底有没有dare not to do,以及相关用法...看了那么多类似问题没有一个回答讲清楚的, 请问：happen的用法.eg:what happened,what's happen的区别 happen to have down的意思那用法呢