Review question 1: The first four questions are all pictures, starting with the fifth picture. 5: cut 2 knives, and you can cut up to 4 pieces; Cut 3 knives, and you can cut 8 pieces at most. 6: D7: Only (1) (3) is correct. 8: (1) Correct. If the plane passing through A is equal to C, then A//B, so B//C, so B//∞. ⑵ Correct and parallel transitivity. (3) (4) Correct. 9. The quadrilateral EFGH is an isosceles trapezoid, and the rest of the questions are all processes and can't be typed. You borrow a book from your classmate to write.