题目内容：

A computer can get very hot when it works on a lot of programs. It can cost a lot to cool the computer. So some scientists want to know what would happen if the heat from the computer could be used.

        Large Internet companies such as Google and Microsoft have thousands of computers. As these computers deal with information， they produce lots of heat， so they need huge cooling systems. These systems send the heat into the air.

        A company in Holland thinks paying to make the computers work and then paying again to cool them are a waste of energy. So the company developed a special device—the e-Radiator.

        Boaz Leupe， head of the company， says that e-Radiator works as a heating system and saves money. He explains that the energy is used twice—once to heat the home and once to cool the computer and that the users don’t have to pay to cool their computers.

         Five homeowners in Holland are testing the heating system in their homes.

     “We pay for the computer using， so， in that way， homeowners get heating for free.” Boaz says.

     Jan Visser is one of the homeowners. “If you use the computer more， the e-Radiator producers more heat，” he says， “It cannot provide enough heat if you don’t use your computer often.” But he is ready to try it. It’s a great help for his family.

      The company says e-Radiators produce heat temperatures of up to 55℃. It says the system could save its users about $440 a year.

1.Before the e-Radiator appears， usually the heat of a computer ______.

A. is sent into the air

B. helps the five homeowners

C. is used twice

D. makes the computer work better

2. The e-radiator is mainly used _____.

A. to help Microsoft

B. to provide heat

C. to heat the computer

D. to drive the computer

3.How much could the system save its users a month?

A. About 20 dollars.                      B. About 440 dollars. 

C. About 36 yuan.                        D. About 36 dollars.

4. The best title of the passage may be “_____”.

A. An Environment Problem   

B. The Future Computers 

C. A New Way to Heat Homes 

D. The Energy to Be Wasted