Transparency, as a new educational technology devel-oped gradually in the process of teaching reform of our country, stimulates a passion for learning through simulation, integrity, variability generated from optical instruments. It can save teach-ing time, improve teaching efficiency, which can help solve the focal and difficult points. It can realize the transformation be-tween big and small, motion and station, partial and whole, plane and solid in accordance with different teachings. Meanwhile, it is lively and interesting, efficient and time-saving, simple to oper-ate, easy to make and well-adapted.%投影教材是我国在教学改革中逐步发展起来的新型的教育技术。投影教材是通过光学仪器产生的以模拟性、整观性、可变性来激发学习热情。投影教材可节省教学时间，提高教学效率，有利于解决教学中的重点、难点。它可以根据授课的需要，实现大与小、静与动、局部与整体、平面与立体的转化，同时，投影教材还有着生动有趣、高效省时、操作方便、易于制作、适应性强等优点。
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