To teach students a glass of water, teachers should have a bucket of water. In other words, compared with the knowledge of "a glass of water" obtained by students, teachers must have ten times and one hundred times the knowledge of "a bucket of water" obtained by students. This vividly reflects people's expectation of teachers' knowledge stock, and also reflects the general view of teachers' knowledge in traditional society. "Learning to be a teacher", teachers must have rich knowledge to teach students well, which is undoubtedly very correct.

However, now many people begin to question this sentence, thinking that it is not enough for a teacher to have a bucket of water to give students a glass of water. This is just a different way of thinking, if we think more deeply about this sentence. You will find that there are imperfections. Now the speed of knowledge updating is getting faster and faster, and the number is increasing; There are more and more ways to spread knowledge, and the spread speed is getting faster and faster. In this social background, teachers' view of knowledge must be changed, and teachers must establish the concept of lifelong learning, keep charging, keep pace with the times, and change the original "bucket of water" into "running water". At the same time, we should change the image of "teacher" in the past and be a conscientious guide.

Therefore, this sentence can be changed to "give students a glass of water, and teachers should have running water", which is also a major change in educational concepts.