答案:Before he arrived in Beijing,he knew everything about the accident. 或:He knew everything about he accident before he arrived in Beijing. 翻译:在他到北京之前,他就知道那场意外的一切事情. 不明白的再问哟,请及时采纳,多谢!
He had known everything about the accident before he arrived in Beijing. 或 Before he arrived in Beijing, he had known everything about the accident 祝你假期愉快!加油!不明白再问!如果帮到你,请采纳,谢谢!