分析并指出下列关系中的变量与常量：

（1）球的表面积S cm²与球的半径R cm的关系式是S=4πR²；

（2）以固定的速度v₀米/秒向上抛一个小球，小球的高度h米与小球运动的时间t秒之间的关系式是h=v₀t﹣4.9t²；

（3）一物体自高处自由落下，这个物体运动的距离h m与它下落的时间t s的关系式是h=$\frac{1}{2}$gt²（其中g取9.8m/s²）；

（4）已知橙子每千克的售价是1.8元，则购买数量W千克与所付款x元之间的关系式是x=1.8W．

    My name is John Brown. I am a school boy. My school is 1my home. Every day it takes me a lot of time 2 there. The road is not good, so I can't 3my bike to school. I often take a bus there. It usually 4 me forty minutes to get there 5.I 6 at seven every morning. I have no time for breakfast at home. I often have something for breakfast on the bus 7 at school. I don't want to  8school. Some students in our school take buses to school. Some students walk to school 9 their homes are not far.10students ride bikes