某物体作直线运动的速度﹣时间图象如图所示，根据图象回答：

老花镜的“度数”等于它的焦距的倒数乘100，请设计一个测老花镜度数的简单方法，要求写出所用器材、操作步骤和计算公式。

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

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。

    The person that we should learn needn't be rich or famous. It can be a person we live with. For I, it's my father. I still remembered the days when I was a child. Although he had plenty of works to do, he still stayed with me but played games with me. With time gone by, I'm in Senior 3 now. It is I who has no time to stay with him now! However, he is still behind me and tries his best to make it a better life for our family. What selfless he is! I am very gratefully to him. He is not only my father, but also a hero living with me!