我平时很爱观察,无论遇到什么东西都喜欢打破砂锅问到底。有一次,我和妈妈在街上散步,在马路上看见每隔一段距离,就有一个圆圆的下水道盖子。我问妈妈:“妈妈,下水道的盖子为什么是圆的?”妈妈也回答不上来,说:“你这孩子,凡事总爱问个为什么,要想知道答案,为什么不自己开动脑筋思考呢?”回到家后,我一直在想这个问题。别的圆形都是直线图形,只有圆形是曲线图形,是不是因为无论从什么 I usually love observation, no matter what I like to break the casserole asked in the end. Once, my mom and I walked down the street and saw a round sewer lid on the road at regular intervals. I asked my mom: “Mom, why the lid of the sewer is round? ” Mom can not answer, saying: “You kid, always love to ask why, in order to know the answer, why do not you think it? ? ”After I got home, I was thinking about it. Other circles are straight lines, only the circle is a curve, is it because no matter from what