介绍： 版权归原作所有，仅供此学习，若有侵权请告知删除。
[12:06.83]The last reading.
[12:09.03]Hydroelectric Energy
[12:11.54]Hydroelectric energy is made by flowing water.
[12:15.93]Most hydroelectric power plants are located on dams,
[12:20.18]which block the river and create an artificial lake.
[12:24.67]A control...

介绍： 版权归原作所有，仅供此学习，若有侵权请告知删除。
[12:06.83]The last reading.
[12:09.03]Hydroelectric Energy
[12:11.54]Hydroelectric energy is made by flowing water.
[12:15.93]Most hydroelectric power plants are located on dams,
[12:20.18]which block the river and create an artificial lake.
[12:24.67]A controlled amount of water is forced through tunnels in the dam to produce electricity.
[12:31.63]Hydroelectric energy has some advantages.
[12:35.45]First, it's fairly inexpensive to produce.
[12:39.12]Dams don't need to be complex,
[12:41.37]and the resources to build them are not difficult to obtain.
[12:45.46]Second, its source is available to many people as rivers flow all over the world.
[12:52.21]Third, it's fairly reliable for the flow doesn't depend on the weather but the control by engineers.
[13:00.18]However, it has certain disadvantages too.
[13:03.68]Hydroelectric power plants are damaging to the environment.
[13:08.35]The lake created behind the dam drowns the original river habitat deep underwater.
[13:15.23]Besides, these plants don't work for a very long time,
[13:19.56]because the dirt from a river bed builds up behind the dam and slows the flow of water.