题目内容：

The discussion on renewable energy has been going on for at least a decade and people have relied on fossil fuels almost entirely for more than a century. However, the situation when fossil fuels were the most efficient and the cheapest source of energy has been left far in the past. Many countries such as Germany and Sweden have already made significant efforts to fix this situation, employing numerous power plants working on the renewable resources of energy. The most effective among these resources is geothermal (地热的) energy.

Geothermal energy does not depend on the world’s economic and political situation as strongly as fossil fuels do. Besides, extracting (提炼) fossil fuels adds to the price of energy produced from them. Therefore, geothermal energy is much cheaper than traditional ones, saving up to 80% of the costs over fossil fuels.

Being a renewable resource, geothermal energy produces less waste and pollution than traditional energy sources. In geothermal systems, carbon dioxide makes up about 10% of air produced. Overall, in order to produce the electricity that can be used for one hour, the geothermal systems produce 0.1 pound of carbon dioxide and other harmful gases. For a comparison, a power plant producing from gas produces up to 2 pounds of carbon dioxide into the atmosphere, and those power plants that work on coal (煤) produce an astonishing 3.6 pounds of greenhouse gases.

Low costs is another reason why using geothermal power plants should be the first choice for many countries. Geothermal heat systems require 25% to 50% less energy for work compared with the traditional systems for heating or cooling. Besides, geothermal equipment is less big: due to the very nature of geothermal energy, geothermal power plants have only a few moving parts, all of which can be easily sheltered inside a relatively small building. What’s more, the life span of geothermal equipment is rather long. All these make geothermal power stations easy to build and keep.

1.Fossil fuels are more expensive than geothermal energy partly because _______.

A. it is free to use geothermal energy

B. fossil fuels are nearly used up

C. the production of fossil fuels costs a lot

D. geothermal energy doesn’t depend on political situation

2.According to Paragraph 3, what can be concluded from the comparison?

A. Coal is much more efficient than gas.

B. Gas and coal are often used to produce electricity.

C. Geothermal energy is environmentally friendly.

D. The geothermal systems don’t produce harmful gases.

3.Geothermal equipment is usually not as big as that of traditional energy because of ________.

A. the nature of geothermal energy    B. geothermal power plants

C. life span of geothermal equipment    D. the small buildings

4.What is the main idea of this passage?

A. Many countries have benefited from geothermal energy.

B. Geothermal energy is well accepted.

C. Geothermal energy has many advantages.

D. Fossil fuels are being run out of.