假定英语课上老师要求同学们交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。错误涉及一个单词的增加、删除或修改。
增加：在缺词处加一个漏字符号（∧），并在其下面写上该加的词。
删除：把多余的词用斜线（\）划掉。
修改：在错的词下划一横线，并在该词下面写上修改后的词。
注意：1）每处错误及其修改均仅限一词；
2）只允许修改10处，多者（从第11处起）不计分。
One day I went with my dad to a store near our home. Just inside the door stood the most beautiful bicycle I have ever seen. No other kids in our town rode one like it. My dad must have noticed it. Bend down, he asked if I liked the bicycle, who price was a little high. I nodded. To my surprise, he bought it without any hesitate. I felt quite excitedly.
Later, my father shared with me his experiences of those of his school day. My grandparents had no money for even such the thing as a pencil, and he never dared to ask my grandpa for one. Tears filled with Dad's eyes whatever he recalled his childhood. He said he would do his best get his child what he wanted.
下降到虚线位置，但圆环仍保持在原来位置不动。则在这一过程中，环对杆的摩擦力F1和环对杆的压力F
2的变化情况是 