一、问题的提出随着新一轮课改的不断推进与深入,如何使课堂教学有效甚至高效倍受关注。习题的变式教学是化学课堂教学的一种常用形式,它对课堂教学有着重要的导向和评价作用。笔者通过近阶段的听课发现:越来越多的化学教师正尝试着利用变式这一“法宝”进行教学,这种形式的教学使得化学课堂变得丰富而又精彩,其效果也 First, the question raised With the continuous promotion and deepening of a new round of curriculum reform, how to make classroom teaching effective and even more effective attention. Exercises of the variant teaching is a common form of chemical classroom teaching, classroom teaching it has an important role in guiding and evaluation. Through the recent lectures, the author finds out that more and more chemistry teachers are trying to use the variant “magic weapon” for teaching. This kind of teaching makes the chemistry class rich and wonderful, and its effect is also