是什么事使他不能参加我们的会议仍然是个谜的翻译：What prevented him from attending our Conference is still a mystery 什么意思？中文翻译英文，英文翻译中文，怎么说？

青云英语翻译

What is the thing that he can not attend our meetings are still a mystery

What prevented him from attending our Conference is still a mystery

Was any matter enables him to attend our conference still was a riddle

Is that what it was that he was unable to participate in our meeting is still a mystery

What prevented him from attending our Conference is still a mystery