把横线上的数改写成用“亿”作单位的数．按顺序填写，分别是____，____，____。

如图，几何体是由底面圆心在同一条直线上的三个圆柱构成的，其俯视图是（　　）

​

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 teenage year from 13 to 19 were the most difficult time for me. They were also the best and worse years in my life. At the first, I thought I knew everything but could make decisions by myself. Besides, my parents didn't seem to think so. They always tell me what to do and how to do it. At one time, I even felt my parents couldn't understand me so I hoped I could be freely from them. I showed them I was independent by wear strange clothes. Now I am leaving home for college. At last, I will be on their own, but I still want to have my parents to turn whenever I need help.