سؤال ۱۱، زبان انگلیسی ۳، خرداد ۱۳۹۹

متن زیر رابخوانید و به سوالات داده شده هر قسمت پاسخ دهید.The research for new sources of energy has led into various ways. To produce any type of energy, the resources of the earth are used. The main resources of the earth are fossil fuels such as natural gas, oil and coal. Electricity is generated from coal, oil and natural gas, but the process has been proven to be expensive.Experimental works are in progress to produce energy from other resources. Scientists and experts spared no pains to search for new ways of producing new source of energy. For instance, electricity has been produced with giant wind turbines. Geothermal power or the heat from the earth is also being tested to produce energy. Many societies are burning rubbish and other biological waste products to generate electricity. Not only changing unwanted products to gas or oil is a cheap way to produce energy, but also it is an effective way to get rid of waste.Some experts expect service companies to expand hydroelectric power generated from streams and rivers. As an example, 50 years ago hydroelectric power provided one-third of the electricity used in the United States but today it includes only 4%. The oceans are another possible source of energy. Scientists are studying ways to change the energy of oceans’ tides and waves into electricity. Experiments are also underway to make use of temperature differences in ocean water to produce energy.Clean energy resources are vastly respected, valued, and used all over the world to keep the environment clean. As a result, scientists try to introduce new types of energy resources called clean energy resources to nations of the world.