The ancient Loulan City lies on the west bank of Lop Nur Lake in Xinjiang region.The city was founded in the 2nd century BC in an oasis (绿洲) on the Silk Road.But it became less powerful and strong after its 800 years of development, and disappeared suddenly in the middle of the 6th century AD.At the beginning of last century, a Swedish explorer Sven Hedin discovered the city buried in the desert, which attracted attention from all over the world.

　　The city has already totally turned into dust.But archaeologists (考古学家) believe there was a water tunnel running through the city and dividing it into two different functional parts.Large numbers of potsherds (陶瓷碎片), wood pieces, coins, pieces of jewellery and wood slip documents provide us with plenty of information about the ancient city before it disappeared.

　　The study of the materials of the ruins of Loulan City perhaps can tell us why it disappeared.The archaeologist found that the Loulanese preferred Sun tomb which consisted of 7 circles of logs which became thicker and thicker from center to the outer circle, just like the sun shining.The unique but spectacular (壮观的；令人惊叹的) burying form was quite popular at that time but sped up the disappearance of Loulan City.A large amount of forest was cut down, which made Loulan City destroyed by the sandstorms at last.

　　Section_ⅠWelcome to the unit & Reading - Pre­reading

　　　　　　　　　　　　　　　　　　　　　　　　　　对应学生用书P62