sixty-four /ˌsɪksti ˈfɔː(r)/ ●the sixty-four thousand dollar ˈquestion ( the million dollar ˈquestion) a very important question which is difficult or impossible to answer难以（或不可能）回答的重要问题；重量级难题◆The sixty-four thousand dollar question for modern astronomy is ‘Is there life elsewhere in the universe?’ 当代天文学中一个重大难题是“宇宙中的其他地方有生命存在吗？”ORIGINThis phrase originated in the 1940s as ‘the sixty-four dollar question’. It came from a popular US radio quiz programme at the time on which the top prize was $64.这个短语源于 20 世纪 40 年代美国一档颇受欢迎的广播问答节目“ 64 美元奖金的问题”，该节目的头等奖是 64 美元。