立体几何题由于点、线、面关系复杂,特别是题中未给出图形的情况下,更是感到不易下手,如果能挖掘题设条件,展开联想,巧妙建立相应的长方体模型,充分利用其特性就能使解题思路豁然开朗,而且过程简捷明了.本文列举3例,抛砖引玉. Three-dimensional geometry problems due to the point, line, surface complex, especially in the case of the graph does not give a picture, it is difficult to start, if you can dig the conditions, expand the association, cleverly establish the corresponding rectangular model, make full use of it The characteristics can make the problem-solving ideas suddenly clear, and the process is simple and clear. This article lists 3 cases, throwing bricks to attract jade.