我们通常把幻灯片、录音带、录象带、电影片等算为电化教学材料,这里主要说幻灯片或投影片的编制原则。 电化教学材料的来源有三个:一是买,二是改,三是自己制作。在沔阳自然电教研讨会上我们强调了制片,这对于自然教学来 We usually count slides, audiotapes, video tapes and movies as e-learning materials. Here we mainly talk about the principle of slides or slides. There are three sources of teaching materials: one is to buy, the other is to change, and the third is to make their own. In the Yangyang Nature Audio-visual Seminar we emphasized the production, which for nature teaching