教授收了四个学生，他们分别来自美国、中国、俄罗斯和日本。开学第一天，教授让他们解决一个问题：桌上有一只烧杯，杯内盛有水，比水面低一点的杯壁上有一个小孔，水从孔里不断流出。现在要解决的问题是，怎样迅速制止杯中的水向外流。教授给四位学生一天的思考时间，第二天? The professor has collected four students from the United States, China, Russia and Japan. On the first day of school, the professor asked them to solve a problem: there was a beaker on the table, the cup filled with water, a small hole in the wall of the cup a little lower than the water, and the water continuously flowed out of the hole. The question now to be solved is how to quickly stop the water in the cup from flowing outwards. Professor to four students a day thinking time, the next day?