“happen”这个单词的过去式和过去分词均为“happened”。例如:“Tell me what really happened.”(告诉我究竟发生了什么事。)“Can you confirm what happened?”(你能证实一下发生了什么事吗?)
相关介绍:
All these changes happened over a period of time. (所有这些变化都是在一段时间内发生的。)
You must on no condition tell them what happened. (你决不能告诉他们所发生的事。)
This is the second time it's happened. (这已是第二次了。)