题目内容：

The oldest and most common source(来源) of renewable energy known to man, biomass is one of the most important forms of energy production in the United States and elsewhere．Since such a wide variety of biomass materials is everywhere—from trees and grasses to agricultural and city-life wastes—biomass promises to play a continuing role in providing power and heat for millions of people around the world．

According to the Union of Concerned Scientists(UCS), biomass is a kind of renewable energy source that produces no carbon dioxide(二氧化碳), because the energy it contains comes from the sun．When plant matter is burned, it gives off the sun’s energy．In this way, biomass serves as a sort of natural battery(电池) for storing the sun’s energy．As long as biomass is produced continuously —with only as much grown as is used—the “battery” lasts forever．

According to the Energy Information Administration, biomass has been one of the leading renewable energy sources in the United States for several years running through 2007, making up between 0．5 and 0．9 percent of the nation’s total electricity supply．In 2008—although the numbers aren’t all in yet—wind power probably took over first place because of the rapid development of wind farms across the country．

Producing power from biomass helps reduce some 11 million tons of carbon dioxide each year．Some homeowners also try to make their own heat by using biomass materials．Such practice may save homeowner’s money, but it also produces a lot of pollution．So, the best way is to encourage power plants to use it．

1.Why is biomass considered as “a sort of natural battery”?

A．It burns merely plant matter．

B．It keeps producing electricity．

C．It stores the energy from the sun．

D．It produces zero carbon dioxide．

2.We learn from the text that in 2008 ______．

A．wind power would be the leader of renewable energy．

B．there was a rapid growth of electricity production

C．biomass might become the main energy source

D．0．5~0．9 of power supply came from biomass

3.Why does the author encourage power plants to use biomass?

A．To prevent the waste of energy．

B．To increase production safety．

C．To reduce pollution．

D．To save money．

4.Where does the text probably come from?

A．A research plan．

B．A science magazine

C．A book review．

D．A business report．