Known: as shown in the figure, RT △ ABC ≌ RT △ ade, ∠ ABC = ∠ ade = 90 °, try to connect two line segments by taking the points marked with letters in the figure as the end points. If the two line segments you connect satisfy one of the equal, vertical or parallel relationships, please write it out and prove it
Answer: the first kind: connect CD, be, get: CD = be