2. Verification: Two lines perpendicular to the same line are parallel. Draw a picture, write what is known, verify and prove it in three ways. ) (10)
3. As shown in the left figure below, it is known that EF⊥AB, the vertical foot is F, CD⊥AB, and the vertical foot is D, ∠ 1=∠2. Verification: ∠AGD=∠ACB. (1 0).
4. As shown in the right figure above, it is known that ∠ B+∠ Bed+∠ D = 360. Verification: AB ∠ CD.
5. According to the diagram, find out at least five problems that can make AD‖BC hold. (10)
6. As shown in the figure, it is known that AB ‖ ef, ∠ C = 90, and verification: X+Y-Z = 90 (10).