B The world is not coming to an end on December 21, 2012, the US space agency insisted Mon

B
The world is not ing to an end on December 21, 2012, the US space agency insisted Monday in a rare campaign to dispel widespread rumors fueled by the Internet and a new Hollywood movie．
The latest big screen offering from Sony Picture, 2012, arrives in theaters on Friday, with a 200-million-dollar production about the end of the world supposedly based on myths backed by the Mayan calendar．It is claimed that the end of time will e as a Planet X---or Nibiru---heads toward or collides with the Earth．
Some websites accuse NASA of hiding the truth on the planet’s existence, but the US space agency condemned such stories as an “Internet hoax”．“There is no factual basis for these claims,” NASA said in a question-and-anwser posting on this website．“If such a collision were real, astronomers would have been tracking it for at least the past decade, and it would be visible by now to the naked eye．Obviously, it does not exist．Credible scientists worldwide know of no threat associated with 2012,” it insisted．“After all, our planet has been getting along just well for more than four billion years,” added NASA．
There is another planet, Eris, floating in space．But the small planet similar to Pluto will remain safely fixed in the outer solar system and it can e no closer than four billion miles to the Earth, according to NASA．
Earlier theories set the disaster for May 2003, but when nothing happened the date was moved forward to the winter in 2012 to coincide with the end of a cycle of the ancient Mayan calendar．
NASA insisted the Mayan calendar in fact does not end on December 21, 2012, as another period begins immediately afterward．
And even if the planets were to line up as some have forecast, the effect on our planet would be “negligible（unimportant）”, NASA said．
“And while ets and asteroids （小行星） have always hit the Earth, big hits are very rare,” NASA noted．The last major impact was believed to be 65 million years ago, resulting in the end of dinosaurs．
“We have already determined that there are no threatening asteroids as large as the one that killed the dinosaurs,” the space agency said．
49．     played a key role in the spread of the rumors．
A．A new book               B．The Internet and a new Hollywood movie
C．NASA                   D．An Indian calendar
50．We can infer that     ．
A．people didn’t take the rumor seriously
B．Planet X --- or Nibiru does exist
C．astronomers have been tracking Planet X for over ten years
D．the rumor caused a panic among some people
51．NASA thinks that Eris     ．
A．might have a threat to the Earth     B．doesn’t have any threat to the Earth
C．is too far away to be visible       D．is similar to our planet, where life might exist
52．Which of the following is the best title?
A．New Hollywood movie 2012
B．December 21, 2012, Not the end of the world
C．End of the ancient Mayan calendar
D．How rumors came into being49-52:    BDBB