题目

The Great Wall is one of the most famous historical sites in the world today. Do you know that an Englishman has spent years protecting it? William Lindesay got interested in the Great Wall when he was a schoolboy. In order to realize his dream of visiting it, he majored in (主修) Geography at college. In April 1987, he arrived in China and spent 78 days walking along the Great Wall. During the journey, William found that the Great Wall was actually not the same as what he had seen in pictures. “Some people scribble (乱涂) on it and some throw rubbish all around,” he said. From then on用化学符号填空： （1）正三价的铝元素                                     （2）两个五氧化二磷分子                   （3）形成酸雨的气体                                     （4）天然气的主要成分                      （5）骨质疏松患者应补充的元素