高考试题中的立体几何题,常以简单几何体为依托,讨论其中线和面的相对位置及空间角的计算,其中不少题不是呈现标准的几何体,而是经过截、切的多面体,从而增加了识图的难度,如果能够通过补形构造出几何体的本来面目,将会使难度得到大幅度降低。下面以几道高考原题为例说明这个问题。 Three-dimensional geometric questions in the entrance examination questions, often relying on a simple geometry to discuss where the relative position of the line and the surface and the calculation of the spatial angle, many of which are not the standard geometry, but through truncated, cut polyhedron, thereby increasing Understand the difficulty of the figure, if we can shape the original shape of the body through the shape, will make the difficulty is greatly reduced. The following example to illustrate the problem with several college entrance examination.