大单元教学背景下中职机械制图中两正交圆柱体相贯线的教学探讨
Teaching Discussion on Intersection Line of Two Orthogonal Cylinders in Mechanical Drawing of Secondary Vocational School under the Background of Large Unit Teaching

笔者在多年中职机械制图教学观察中发现，相贯线的投影作图在学生学习机械制图的后期绘图中，很容易出错，是机械制图中的难点和重点。以此内容为例，本文着重阐述学生在大单元教学背景下如何学习，以及教师在教学过程中如何展开实施。
After many years of teaching and observation of mechanical drawing in secondary vocational school, the author found that the projection drawing of intersecting line is easy to make mistakes in the later drawing of mechanical drawing, which is the difficulty and key point in mechanical drawing. Taking this content as an example, this paper expounds how students learn and how teachers carry out teaching in the context of large unit teaching.