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纸桥:美国科学家研制一种奇特的纸桥,桥的跨度 15米,宽3米,能通过3吨重的汽车。这种纸里面混有金属纤维,强度极高。草桥:在秘鲁阿普里玛河一带的印第安人,至
Paper Bridge: American scientists have developed a unique paper bridge with a span of 15 meters and a width of 3 meters that can pass a 3-ton car. This type of paper is mixed with metal fibers and is extremely strong. Caoqiao: Indians along the Apurima River in Peru, to