According to the meaning of the question, AB is parallel to CD, and the extension line DE makes PE and AB intersect at point E, then the angle CDP= angle AEP is known.

According to a triangle, the complementary angle of one angle is equal to the sum of the other two angles in the triangle, and the angle ABP- angle CDP= angle BPE= angle BPD.

The positions of AB and CD are interchanged as follows: Let the extension line BE make PE and CD intersect at point E, then the angle ABP= angle CEP is known.

According to a triangle, the complementary angle of one angle is equal to the sum of the other two angles in the triangle, and the angle CDP- angle ABP= angle BPE= angle BPD.