Dujiangyan is the oldest man-made water system in the world, and a wonder in the development of Chinese science.     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 in which Dujiangyan now stands     3    (suffer) from regular floods caused by overflow from the Minjiang River.     4    (help) the victims of the flooding, Li Bing, the 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 floodwater while leaving the river flowing naturally.     5    (good) still, the extra water could be directed to the dry Chengdu Plain, making     6     suitable for farming.

Once the system was finished, no more floods occurred and the people were able to live     7    (peaceful). Today, Dujiangyan is admired by scientists from around the world because of one feature. Unlike modern dams     8     the water is blocked with a huge wall, Dujiangyan still lets water flow through the Minjiang River naturally,     9     (enable) ecosystem(生态系统) and fish populations to exist     10     harmony.