"There are three boxes, one contains only apples, one contains only oranges, and one contains both apples and oranges. The boxes have been incorrectly labeled such that no label identifies the actual contents of the box it labels. Opening just one box, and without looking in the box, you take out one piece of fruit. By looking at the fruit, how can you immediately label all of the boxes correctly?"
“有三个箱子,一个箱子中只有苹果,一个箱子里只有橘子,一个箱子里既有苹果又有橘子。这些箱子的标签都不正确,所以不能通过标签辨认出箱子里的实际内容。只打开一个箱子,不能看箱子里面是什么,只拿出里面的一个水果。通过这个水果,你如何立即给所有的箱子贴上正确的标签?”