The Dujiangyan is the oldest man-made water system in the world, and a wonder in the development of Chinese agriculture.     1     （build）over 2,200 years ago in what is now Sichuan Province in Southwest China, this amazing engineering     2    （achieve）is still used today.

In ancient times, the region where Dujiangyan now stands     3    （suffer）from regular floods from the Minjiang River.     4    （help）the victims of the flooding, Li Bing,     5     region governor, together with his son, decided to find a solution. Li designed a series of channels built at different levels along Mount Yulei that would take away the floodwaters while leaving the river flowing naturally.     6    （good）still, the extra water could be directed to the dry Chengdu Plain, making     7     suitable for farming.

Once the system     8    （finish）, no more floods happened and the people were able to live     9    （peaceful）. Today, Dujiangyan is admired by scientists from around the world because of one feature. Unlike modern dams,     10     the water is blocked with a huge wall, Dujiangyan still lets waterflow through the Minjiang River naturally, making the ecosystem（生态系统）and fish populations exist in peace.