题目

A、B、C、D、E五种有机物，它们分子中C、H、O三种元素的质量比都是6∶1∶8。在通常状况下，A是一种有刺激性气味的气体，对氢气的相对密度为15，其水溶液能发生银镜反应。B的相对分子质量是A的6倍，C和B是同分异构体，两物质都是具有甜味的白色晶体，但B常用作制镜工业的还原剂。D和E两物质的蒸气密度都是2.68 g/L(标准状况下)，它们互为同分异构体，但D的水溶液能使石蕊试液变红，而E是不溶于水的油状液体，具有水果香味。试写出A、B、C、D、E的任务型阅读　下面是某次摄影展中的照片及有关信息，阅读后回答有关问题。Famous Landmarks★The Great Wall of China was built in 214 B. C. . It is the largest structure ever built. There is an old saying about it: He who doesn’t reach the Great Wall is not a true man. ★The Colosseum in Rome(古罗马圆形大剧场) was opened in 80 A. D. . It was sometimes filled with water for ship battles.★The Statue of Liberty in New York was opened in 1886. It was a gift to Americans from French people.★The Eiffel Tower in Paris was completed in 1889. It was built for the 100th anniversary of the French Revolution（法国大革命）.（1）What does the underlined sentence mean in Chinese?（2）When was the Colosseum in Rome opened?（3）What did the people of France give Americans as a gift?（4）What was the Eiffel Tower built for?