题目

Mr. Black was working in a factory in a big town. He liked 1 very much, and was very good 2 it. When he was free, he 3 down to a small river behind the factory and tried 4 some fish, but there were very few there, 5 the water wasn’t clean. One summer he went to the seaside during his holiday and stayed at a small cheap hotel.“I have never fished in the 6 before.” He thought. “It will be more interesting than fishing in our river.” 7 first he caught a lot of fish and was very 8 . He gave them to the hotel and they cooked them for guests, and he enjoyed himself very much. 化合物A最早发现于酸牛奶中，它是人体内糖代谢的中间体，可由马铃薯、玉米淀粉等发酵制得，A的钙盐是人们喜爱的补钙剂之一。A在某催化剂的存在下进行氧化，其产物不能发生银镜反应。如图所示，在浓H2SO4存在下，A可发生如下反应： 试写出： （1）化合物的结构简式：A____________；B_____________；C_____________。 （2）写出化学方程式并注明反应类型： A→E__________________________________________ A→F__________________________________________