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.

如图所示，①﹣⑥表示人体的某个器官或结构，A﹣E表示人体内的某项生理过程，请据图分析并回答问题

 有一包白色粉末，可能含有氯化钡、氢氧化钠、碳酸氢铵、氯化钠、无水硫酸铜、碳酸钙中的一种或几种．为确定其组成．进行如下实验：

①取少量该粉末置于烧杯中，未嗅到任何气味；向烧杯中加人适量的水，充分搅拌，静置后，观察到上层溶液呈无色，烧杯底部有蓝白色固体；过滤．

②向上述滤液中滴加几滴硝酸银溶液，溶液变浑浊．

③将上述滤渣投入盛有足量稀盐酸的烧杯中，充分搅拌，有无色无味的气体产生．烧杯底部有白色固体剩余．

则下列说法正确的是（　　）