My name is Zhang Peng. I have a friend. His name is John. He has a grandpa and a grandma. They are seventy years old. They are at home. John's father works in a school. His mother is a doctor. John is a good student. They are very busy. They all get up early in the morning. John often helps his grandparents cook breakfast. There is a big garden and many young trees in front of his house. We can play games there. It's great.

已知：在Rt△ABC中，∠C=90°，sinA、sinB是方程x²+px+q=0的两个根．

成语“南辕北辙”，指要到南方去，却驾着车往北走。比喻行动和目的相反，最后不能达到目的地。如果“东辕西辙”，理论上可以到达目的地，解释其原因正确的是（　　）

①经线等长；纬线不等长  ②经线指示南北方向；纬线指示东西方向  ③地球自西向东运动

④经线是圆；纬线是半圆  ⑤地球在公转时，地轴是倾斜的  ⑥经线是半圆；纬线是圆。