随着高考制度的改革，跨学科综合能力的培养日趋重要。习题教学是训练学生各方面能力的有效途径之一。笔者教学中分析归纳２~ｎ规律，巧解生物学习题，既使解题快速、简捷、准确，又提高了综合素质，收到了事半功倍的效果。 １．一个ＤＮＡ分子连续复制２~ｎ次后，产生的ＤＮＡ With the reform of the college entrance examination system, the development of interdisciplinary comprehensive ability is increasingly important. Exercise teaching is one of the effective ways to train students’ abilities in all aspects. In the author’s teaching, he analyzed and generalized 2~n rules and solved the biology problem skillfully. Even if the problem solving is fast, simple and accurate, he also improved the overall quality and received a multiplier effect. 1. After 2 to n consecutive copies of a DNA molecule, the resulting DNA