题目内容：

Wikipedia is a free-access, free content Internet encyclopedia(百科全书), supported and hosted by the non-profit Wikipedia Foundation. Wikipedia is ranked among the ten most popular websites and is considered the Internet’s largest and most popular general reference book. Now, Wikipedia is becoming Wookiepedia as scientists hope the informative website will help us reach out to intelligent life forms. So aliens can learn about the human race.

Astronomers would like to beam (播送) the entire contents of Wikipedia into space in the hope of contacting aliens. They want to send messages to hundreds of star systems and planets 20 light years away using radio telescopes. The Search for Extraterrestrial Intelligence Institute, in California, wants to use powerful radio telescopes to try to reach Chewbacca and his mates in a galaxy（银河系）far away.

The plans will be discussed by astronomers at the weekend as some scientists fear the reply from ET might not turn out to be friendly. Institute scientist David Black said, “One question is if there are dangerous creatures we might be drawing their attention to ourselves. Another is if we go ahead, what message should be sent? There could be many civilizations out there，but if they are all listening and no one is broadcasting or responding, then nothing will happen.”

Professor Stephen Hawking, who has warned that intelligent aliens probably exist and we should keep a safe distance from them, is among those. “If aliens visit us, the outcome would be much as when Columbus landed in America which didn’t turn out well for the Native Americans,” he said.

Signals from Earth’s radio and TV broadcasts have been heading out in space for some 60 years reaching around 5,000 stars.

1.What does the underlined word those in the fourth paragraph refer to?

A. aliens from space

B. astronomers sending signals

C. scientists for the plans

D. scientists against the plans

2.What has Prof. Stephen Hawking warned?

A. intelligent aliens would probably land in America.

B. the plans will be in vain and nothing will happen.

C. none of the civilizations would reply.

D. aliens would bring disasters to the human race.

3.Which can be the best title?

A. Wikipedia, the most popular website

B. Wikipedia to be beamed into space

C. Wikipedia, aliens’ best friend

D. Wikipedia to result in a disaster