【正确答案】 A

【答案解析】Fossil fuels get their name from their formation from dead plants and animal matters that were compressed and heated over millions of years. According to the U.S. Department of Energy, fossil fuels are used to generate more than 85 percent of the energy used by the country. Alone the transportation sector, oil supplies 99 percent of the energy for cars in the form of petrol and diesel. Natural gas technologies are also being developed for automobiles. Though fossil fuels are important in our life, there are also some limits. Fossil fuels are non-renewable resources because reserves are being depleted much faster than new ones are being made. As more fossil fuels are used, the unused resources will be more costly to collect and prices will rise. At the same time, the production and use of fossil fuels raise environmental concerns. When fossil fuels are burned, they release pollutants that contribute to global warming and acid rain. In the United States, more than 90% of greenhouse gas emissions come from the combustion of fossil fuels.

【正确答案】 B

【正确答案】 C