有一次中国科大的一位教授来校作讲座。讲完后一位学生向他提了一个问题:“平时老师常说我们概念不清。请问,要怎样才算是概念清楚了?”教授略作思索后答道:“我认为所谓概念清楚,是指你对这一概念的理解达到了这样一种程度,当你闭上眼睛时,脑诲中就会像看电影一样,出现一幅完整的活动的图景”。对此我是十分赞同的。 One time a professor from China University of Science and Technology came to the school for a lecture. After the lecture, a student asked him a question: “Often, teachers often say that our concept is not clear. Excuse me, what does it mean to be a clear concept?” The professor replied with some thought: “I think the so-called concept is clear. This means that your understanding of this concept has reached such a level that when you close your eyes, your mind will appear like a movie and a complete picture of the activity will appear." I very much agree with this.