在解决许多有关平行线的问题时,由于题目条件隐蔽,往往需要添加适当的辅助线,才能找到解决问题的突破口.然而,添加合适的辅助线并非易事.事实上,对于某些含“拐角”的平行问题,我们不妨试着从“拐角处”添加平行线来解决.现举例说明.例1如图1,如果∠B+∠D=∠BED,试猜想AB与CD的关系如何,并说明你的猜想理由. In solving many problems related to parallel lines, due to the hidden conditions of the subject, often need to add the appropriate auxiliary line in order to find a breakthrough to solve the problem.However, adding the appropriate auxiliary line is not easy.In fact, for some “ Corner ”parallel problem, we may wish to try from “ corner ”to add parallel lines to solve .Examples .Example 1Figure 1, if ∠B + ∠D = ∠BED, try to guess the relationship between AB and CD How, and explain your guess.