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Experts say a recent change in the color of the Mekong River—from yellowish-brown to sky-blue-could be a worrying sign. They say the change suggests a possible problem 1 (cause)by dams that have been built along the Mekong. The river covers 2 distance of 4, 300 kilometers. It begins high in the mountains of Tibet and flows through China and five other countries.
The Mekong usually has a yellowish-brown color 3 results from the sediment(沉淀物)it normally carries. But recent 4 (report)say it has been running clear and taking on a bluish-green color. At the same time, the water levels 5 (become)unusually low, creating sandbanks that enable people 6 (stand)in the middle of the river. The low water levels 7 (clear)cause problems for fishermen and farmers. But experts in Thailand say the decrease in sediment 8 (represent)a different threat, one that can result in a greater erosion of the sides and bottom of the river.
Experts and people living along the river blame the changes 9 . a large dam upriver in Laos. The dam began operating in October. Critics say it is blocking much sediment from flowing down the river. About 70 million people depend on the Mekong River for water, food, jobs, agriculture and transportation. Critics say several large dam projects along the Mekong are harming the river and 10 (it)environment.
