2012淘金英語專業(yè)四級聽寫 上海外國語大學 請從正文部分開始聽寫
Solar water heaters are used around the world and are not very difficult to build. The system is based on a design developed some years ago. It can heat seventy liters of water to sixty degrees Celsius. It can do this between sunrise and noon on a clear day with an average air temperature of thirty-two degrees Celsius. There are two parts to the solar water heater. One part is made of a sheet of metal painted black. Black surfaces become hotter in the sun than surfaces painted any other color. The second part of the solar water heater holds the water for the system. This storage tank can be a container that holds about one hundred liters. Two rubber pipes are attached to the water storage tank. One pipe lets water flow into the system. The other lets water flow out. The solar water heater will last about two years before the rubber pipes need to be replaced.