请问谁能解释下happen to have

请问谁能解释下happen to have happen to do和happen to be doing 的区别?顺便分别解释下.我问的是happen to be doing 不是happen to doing~ 能帮忙找下LENA的WHAT HAPPEN TO ME happen to dohappen to be doing happen to have done翻译下,还有没有其他的词语也能这样用,这种用法叫什么名字,再多举些例子 the biggest thing to happen to iphone since iphone这句话怎么翻译,要能解释得通的 happen的过去分词能作定语修饰名词?There have been many changes ( ) in my school in the last three yearsA happen B happened C happening D to happen 最好能说明下每个选项 happen to sb和happen to do sth 造句并解释造的句子 The mother who lost her son insisted the careless driver was to blame for the traffic accident happening yesterday.请问下happening能换成happened吗?为什么happen做非谓语动词不是可以用过去分词的吗？ happen to happen to happen to 请问下通过80PLUS认证的电源是什么意思呢?谁能解释下, 请问谁能解释下这句话：I already spend my evenings doing things I don't really know how to do yet. 请问是anything didn't happen to...还是something didn't happen to... 为什么,谁能解释下, 谁能解释下怎么回事 谁能解释下原因 “闲云野鹤”谁能解释下.