A、Nuclear weapons. B、Alien kidnapping. C、Human extinction. D、Dangerous infection. D由文章中的话You could be infected with a disease to

Stephen Hawking
    Life on other planet is likely, but intelligent life is less likely. Famed astrophysicist, Stephen Hawking has been thinking a lot about the cosmic question; Are we alone? "The answer is probably not," he says. "If there is life elsewhere in the universe," Hawking asks "why haven’t we stumbled onto some alien broadcasts in space? Maybe something like ’ alien quiz show’ ?" Hawking’ s comments were part of the lecture at George Washington University on Monday in honor of NASA’ s 50th anniversary. He theorized that there are possible answers to whether there is extraterrestrial life. One option is that there likely isn’ t any life elsewhere or maybe there is intelligent life elsewhere. But when it gets smart enough to send signals into space, it’ s also smart enough to make destructive nuclear weapons. Hawking said he prefers the third opinion. "Primitive life is very common , and intelligent life is fairly rare. " He then quickly added "Some would say it has yet to occur on earth. " So should you worry about aliens? Alien abduction claims come from the "weirdos" and are unlikely. However, because alien life might not have DNA like us, Hawking warned, "Watch out if you would meet an alien. You could be infected with a disease to which you have no resistance. " The 66-year-old British cosmologist who suffers from ALS and must speak through a mechanical device believes if the human race is to continue for another million years, we would have to boldly go where no one has gone before. Hawking compared people who don’ t want to spend money on human space exploration to those who opposed to the journey of Christopher Columbus in 1492. "The discovery of the new world made a difference to the old. Just think we won’t have had a Big
Mac or KFC. "
Questions
21. What is the passage mainly about?
22. What is the event when Hawking delivered his lecture at the George Washington University?
23. What is the idea Hawking favors in terms of extraterrestrial life?
24. What is Hawking’ s warning to the encounter of an alien?
25. What is Hawking’ s attitude towards human space exploration?