右表是某指示剂在一定pH范围内所显示的颜色：向滴有少量该指示剂的稀硫酸中，加入氢氧化钠溶液，出现的颜色变化可能是（         ）

    Miss Green is my neighbor(邻居). She 1 at a post office and she meets lots of people2.She is 3 to everyone and likes to help others. She is over fifty years old, 4 she looks very young (年轻）.She is of 5 height and thin. She has long, curly, brown 6.She likes to wear a red T-shirt and jeans. She 7like a movie star. She really likes 8 shopping on weekends and she always buys many beautiful clothes. She always9,“Old people still want 10 beautiful!”People all like her very much.

60kg的人站在跷跷板某一位置时，跷跷板处于如图所示的平衡状态．由此可估测球的质量约为