The property theorem of parallel lines and planes: Definition: A straight line and a plane have no common points (do not intersect), and they are said to be parallel to the plane. Theorem 1: If a straight line outside a plane is parallel to a straight line in this plane, then the straight line is parallel to this plane. Theorem 2: If a straight line outside a plane is perpendicular to the perpendicular to the plane, then this straight line is parallel to the plane.

Judgement method for line and plane parallelism: 1. Use the definition: prove that there is no common point between the straight line and the plane; 2. Use the judgment theorem: starting from the parallelism of the straight line and the straight line, get the straight line and the plane Parallelism; 3. Use the "Plane Parallel" attribute: If two planes are parallel, a straight line in one plane must be parallel to the other plane.