综观许多试题,都是源于书本却高于书本,以至常出常新,但其基本知识点并未变化,只是在某些方面有所创新而已。这就启示我们在教学中要以课本为本,要重视课本习题的内在功能,充分挖掘习题所蕴涵的丰富内容,以适度为原则,从实际出发,通过改变问题的提法,通过变换条件或结论等手段,切实 Looking at many test questions, they all come from the books but are higher than the books, and they are often new. However, their basic knowledge points have not changed, but they are only innovative in some respects. This enlightens us that we should use textbooks as the basis of teaching. We must pay attention to the internal functions of textbook exercises and fully tap the rich content contained in the exercises. Take the principle of appropriateness, proceed from reality, change the formulation of the problem, change the conditions or Conclusion and other means, practical