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先将3020题与解抄录如下: 如果两条直线在两相交平面的每一个平面内的射影都平行,则这两条直线平行。解:设两条直线ι、m,在两相交平面α、β内的射影
First copy the 3020 question and solution as follows: If two straight lines project in parallel in each plane of the two intersecting planes, the two lines are parallel. Solution: Let two lines ι and m be projected in the two intersecting planes α and β.