The Youth Technological Innovations

My grandpa ever told me that the river used to be very clean; you could see the sand at the bottom of river when standing on the bridge.

My grandpa ever told me that the river used to be very clean; you could see the sand at the bottom of river when standing on the bridge. In summer, children liked to swim in it and in winter, they went skating on the ice surface. After foundation of China, in order to prevent flood disaster, the government organized local people to construct Heishan Reservoir.
Copyright @ Beishichao Middle School, Beijing, China 2007