New studies show how food and its production affect the globe and its climate. The process of making a hamburger, for example, requires loss of energy. A cow has to be fed and raised on farmland. And cow waste is a major source of methane（沼气）— 1　 especially powerful greenhouse gas. The cow has to be killed. The meat has to be processed and shipped, 　2　 takes fuel. Most of the cow won’t even be used for meat people eat. By the time a hamburger finally lands o a dinner plate, 　3 has made bad effect on the environment.

We can reduce the production of global warming gases by eating less beef. Other kinds of meat like pork and chicken do 　4　 harm to the environment ―at least 　5　 terms of the amount of greenhouse gases released. 　6　 , all kinds of meat are harder on the planet that vegetables. 　7　 changing our diet to less meat and more vegetables, as it turns 　8　 , may do the world some good.

 

　　The plan: turn Mars into a blue world with streams and green fields, and then fill it with creatures (生物) from the earth. This idea may sound like something from a science fiction (科幻小说), but it is actually being taken seriously by many researchers.

　　This suggested future for the “red planet” will be the main topic for discussion at an international conference hosted by NASA (美国宇航局) this week. Leading researchers as well as science fiction writers will attend the event. It comes as NASA is preparing a multi?billion?dollar Mars research programme. “Turning Mars into a little earth has long been a topic in science fiction,”said Dr Michael Meyer, NASA’s senior scientist for astrobiology (太空生物学). “Now, with scientists exploring the reality, we can ask what are the real possibilities of changing Mars.”

  Most scientists agree that Mars could be turned into a little earth, although much time and money would be needed to achieve this goal.

　　But many experts are shocked by the idea. “We are destroying our own world at an unbelievable speed and now we are talking about ruining another planet,” said Paul Murdin, of the Institute of Astronomy, Cambridge, UK. Over the past months, scientists have become increasingly confident they will find Martian life forms. Europe and America’s robot explorers have found proof that water, mixed with soil, exists in large amounts on the planet.

  In addition, two different groups of scientists announced on March 28 that they had found signs of methane (甲烷) in the Martian atmosphere (大气). The gas is a waste product of living creatures and could be produced by microbes (微生物) living in the red planet’s soil.

　　But scientists such as Dr Lisa Pratt, a biologist at Indiana University, say that these microbes will be put in danger by the little earth project. “Before we have even discovered if there is life on Mars, we are talking about carrying out projects that would destroy all these native lifeforms, all the strange microbes that we hope to find buried in the soil,” said Dr Pratt. This view is shared by Monica Grady, a planetary scientist at the Natural History Museum, London. “We cannot risk starting a global experiment that would wipe out the precious information we are looking for.” she said， “This is just wrong.”

5. The passage is about________.

A. a plan turning Mars into a little earth

B. the necessity of changing Mars

C. Mars supporting life

D. finding water in the Mars

6. Which of the following is NOT the reason why some scientists are against the plan?

A. The project would wipe out all the native lifeforms on the Mars.

B. The project will cost too much money and work.

C. We would ruin Mars.

D. We are destroying our own world at an unbelievable speed. 

7. We can infer from the passage that________.

A. water is a crucial factor for life

B. the project will have little effect on the native lifeforms supposed to live on the Mars

C. Monica Grady is in favour of carrying out the little earth project

D. the idea turning Mars into a little earth is nothing but a science fiction

8. Which of the following supports the conclusion of microbes living in the Mars’s soil?

A. Scientists found liquid water in the Mars.

B. Scientists found signs of methane in the Martian atmosphere.

C. Scientists found a lot of good soil on the Mars.

D. Scientists found some creatures living on the Mars.