英语问题how the accident come about?这里的come about为什么不用过去式

英语语法问题 can you tell me how the accident came about?这里 come a 英语翻译比如说：How did there differences come about?(come about) come about come out与come about的区别 come up 和come about的区别 come along 与come about的区别? 英语短语翻译come along ,come across ,come about 初中英语题用上面的单词填空Find out , come out, care about,by accident,ask my p about the robots come true. Come in.Please!(About the mango.) 与come about 有关 come about 是什么意思?