番茄是重要的园艺作物，为了研究番茄植物的生理现象，有同学做了如下实验：在透明密闭的小室内，放置两个培养罐，分别存放植物培养液和二氧化碳缓冲液（二氧化碳缓冲液可以使室内二氧化碳的量保持恒定），如装置图1．调节灯的光照强度，根据毛细管内水柱左右移动情况，绘制图2．此实验不考虑温度等因素对小室内气体体积的影响．

    A mother and her young son got into a bus in New York City and sat down. The bus conductor（售票员） came to them for their money. The mother said, "I want one ticket（票） to Central Park, "and gave him two dollars. The conductor looked at the small boy for a few seconds and then asked him, "How old are you, young man?"  The mother just began to speak, but the conductor stopped her, and the boy said, "I'm four years old at home, and two and a half on buses and trains."  The mother felt shamed（羞愧）， so she took another dollar out of her bag and gave the money to the conductor. The conductor gave her one and a half tickets.