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大家知道,一个正方体有六个面,从某一方向观察正方体最多只能看到三个面,和这三个面相对的还有三个面都看不到,我们称它们为“阴影面”.有时需要根据题中条件来判定一个正方体的某个“阴影面”,这需要一定的空间想象能力.下面通过一道例题说明其方法.例一个正方体的六个面分别
Everyone knows that a cube has six faces. Observing a cube from a certain direction can only see three faces at most. Three faces that are opposite to these three faces cannot be seen. We call them “shadow faces”. Sometimes it is necessary to determine a “shadow surface” of a cube according to the conditions in the problem. This requires a certain amount of spatial imagination. The following illustrates the method by an example. Example: The six faces of a cube