2012年全国职称英语课件精讲班a592-1-15-2012-90900245.docx

Natural Gas
1 Natural gas is produced from reservoirs deep beneath the earth's surface. It
is a fossil fuel (矿物燃料)meaning that it is derived anic material buried in the earth millions of years ago. The ponent of natural gas is methane (甲烷).
2 The popularity and use of clean natural gas has increased dramatically over the past 50 years as pipeline infrastructure(基础设施) has been installed to deliver it conveniently and economically to millions of residential, commercial and industrial customers worldwide. Today, natural gas service is available in all 50 states in the ., and is the leading energy choice for fueling American homes and industries. More than 65 million American homes use natural gas. In fact, natural gas is the most economical source for home energy needs, costing one-third as much as electricity. In addition to heating homes, much of the gas used in the United States is used as a raw material to manufacture a wide variety of products, from paint, to fibers for clothing, to plastics for healthcare, computing and furnishings. Natural gas is also used in a significant number of new electricity-generating power plants.
3 Natural gas is one of the safest and cleanest fuels available. It emits (发山) less pollution than other fossil fuel sources. When natural gas is burned, it produces mostly carbon dioxide (二氧化碳) and water vapor -- the same substances emitted when