1　实验前预习 ,适当设疑 ,可增加学生的实验兴趣　　预习是学生获得感性知识的前提 ,能更好地理解内容 ,特别是实验前的预习 ,适当设疑 ,可以使学生弄清实验的目的 ,操作中应注意的事项 ,在具体操作时可避免出现的动作错误 ,能节约更多的时间去分析总结本次实验的结果。如在做 1 Prepare for pre-experimental exams and set up appropriate suspicions to increase students’ interest in experiment Pre-requisites are prerequisites for students to acquire perceptual knowledge. They can better understand the content, especially pre-exam preparation and proper questioning, which can help students clarify the purpose of the experiment. The matters that should be paid attention to in the operation can be avoided during the specific operation, and can save more time to analyze and summarize the results of this experiment. As doing