We are going to see the ruins of Machu Picchu in the mountains of the Andes．Machu Picchu was forgotten for centuries but discovered in 1911 by Hiram Bingham, a professor from Yale．It is said to be one of the most beautiful ancient sites in the world． The Incas built the ancient civilization of Machu Picchu between the 12th century and the early 16th century．They spoke a language called Quechua but had no writing system at all．They kept records on various coloured strings with knots called quipu． The Incas proved to be wonderful architects．They built most of their buildings with huge stones but without using any cement（粘结材料） to stick them together．However, the huge stones fit together so perfectly that you cannot force a sharp knife between two blocks．They also built bridges, tunnels through mountains and channels to bring water to their cities—just as the Romans did．The Incas turned the mountains into farmlands and planted corn and potatoes, and raised animals like llama and alpaca for food． Now Machu Piccu has become a major tourist site in Peru, attracting people from all over the world． 小题1:How long ago was Machu Picchu discovered? A．About 20 years ago B．About 50 years ago． C．About 70 years ago D．About a century ago． 小题2:With what did the Incas build their wonderful buildings? A．strings B．stones C．cements D．trees 小题3:The Incas built the following like the Romans except _______ according to the passage． A．roads B．bridges C．tunnels D．channels 小题4:What does the speaker probably do? A．A visitor． B．A guide． C．A teacher． D．A scientist．