材料一：公元1世纪时，古罗马博物学家普林尼在其被誉为百科全书式的著作《自然史》 中把中国叫做“ 丝之国”，古罗马的贵族都以穿着中国丝绸为荣。他还说中国出产的钢很硬，质地很好。17世纪以来，许多欧洲国家的宫廷和王公贵族更是竞相购藏中国的瓷器、漆器和丝绸、刺绣，甚至不惜重金到中国定做，运回国内珍藏起来。

材料二：海上丝绸之路最早可追溯至汉代。唐中后期，陆上丝绸之路因战乱受阻加之同时期中国经济重心已向南方转移，而海路又远比陆路运量大、成本低、安全度高，海路便取代陆路成为中外贸易主通道。海上丝绸之路在宋朝达到空前繁盛，明朝海禁后衰落。

——摘编《海上丝绸之路》

材料三：

用方框中所给单词的适当形式填空。

         As we know, there are many beautiful places in China, such as Hong Kong, Harbin. They attract a lot of people at home and abroad. But it's hard for ____ to choose where they can go. You can tell them ____ Guide to China, which ____ China in detail. If they have no chance to go through the book, you may show them advertisements for traveling, then after ____, they can decide where to go. They will have a good trip and take photos in ____ of it.

人体呼出的气体中二氧化碳增多了，人体产生二氧化碳的部位是（　　）