一天，一名时间管理专家在向一群在商业这一行打拼的学生讲课时，为了清楚地说明一个论点，他用了一个令学生们永远不会忘记的演示来表达。
As he stood in front of the group of high-powered over-achievers he said, "Okay, time for a quiz.” Then he pulled out a one-gallon, wide-mouthed Mason jar and set it on the table in front of him.
他站在这群精力充沛、成就出类拔萃的学生面前，说道：“好的，我们来做个测试。”然后，他拿出一个容量为一加仑的广口玻璃瓶，放在他面前的桌上。
He then produced about a dozen fist-sized rocks and carefully placed them, one at a time, into the jar. When the jar was filled to the top and no more rocks would fit inside, he asked, "Is the jar full?"
接着，他拿出十多个拳头大小的石块，将它们小心翼翼、一块一块地放进瓶子里。等石块填满到瓶口，再也塞不下时，他问：“（你们说），瓶子被装满了吗？”
Everyone in the class said, "Yes." 上课的学生都说：“满了。”
He replied, "Really?" 他的回应是∶“真的满了吗？”