Global warming is the increase of the earth's average surface temperature due to the effect of greenhouse gases,for example,carbon dioxide,which traps heat that would otherwise escape from the earth. After the trees are cut down and more greenhouse gases are released. the "blanket" around the earth called the ozone layer（臭氧层），will get thicker. This catches more heat and makes the earth hotter. Luckily,there are many things that every citizen of the earth can do to help reduce the effects of global warming,and it's never too late or too early for children to take action.
  The children should learn what a carbon footprint is. A carbon footprint is the amount of carbon and greenhouse gases people make as they lead the daily life and go about the normal activities. In other words,the carbon footprint is a measure of the environmental impact（冲击）the life has. To live an environmentally friendly life that doesn't contribute to global warming,people-want to have the smallest carbon footprint possible.
  Almost everything people do contributes to global warming and is related to fossil fuel consumption. These can be direct uses of fossil fuels,like riding in a gasoline-powered car,or indirect contributions to greenhouse gases,such as eating fruits or vegetables that have to be shipped from far way to reach their tables.
  If a child wants to make a contribution to reducing global warming,he should ride a bicycle to the near park,school,his friend's house,or anywhere else instead of taking the car. Or he may try to walk or jog,which is also helpful. In addition,although trains and buses often run on fossil fuels, on average, each person uses less energy and produces less pollution to run. Next time if children with their parents have to get around town or it's too far to walk or bike,take the bus or other public transportation instead of asking for a ride.



What is the main reason for global warming？ ______

A. Too much greenhouse gases are released.
B. The ozone layer has caught more heat.
C. Much more ozone layer has been released.
D. The increase of the earth's inner temperature results in the global warming.

What is the main idea of Paragraph 2？ ______

A. Life has an impact on carbon footprint.
B. The definition of a carbon footprint.
C. People should live an environmental friendly life.
D. People make a huge amount of carbon and greenhouse gases.

The author wants to write the passage for ______ .

A. children
B. parents
C. children educators
D. adults

What can be a suitable title for the text？ ______

A. What Can People Do To Use Less Energy？
B. Why Global Warming Affects Humans' Life？
C. How Can Kids Help Reduce Global Warming？
D. How Does Carbon Footprints Measure Pollution？