【正确答案】正确答案： Hydroelectric Energy Hydroelectric energy is made by flowing water. / Most hydroelectric power plants are located on dams, / which block the river and create an artificial lake. / A controlled amount of water is forced through tunnels in the dam to produce electricity. / Hydroelectric energy has some advantages. / First, it's fairly inexpensive to produce. / Dams don't need to be complex, / and the resources to build them are not difficult to obtain. / Second, its source is available to many people as rivers flow all over the world. / Third, it's fairly reliable for the flow doesn't depend on the weather but the control by engineers. /