五、阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。选项中有两项为多余选项。
We have seen lots of science fiction movies about aliens. People travel to stars and even fight with aliens in the movies. 1. Most of us think it is impossible，just like fairy tales. But the answer of some scientists is “yes”. So they have been searching for aliens in outer space for many years. 2.
Some scientists are used to using radio telescopes to search for aliens in space. In order to find aliens，they have worked hard for over half a century，but so far they have found nothing. Then some scientists guessed aliens might not want to connect with us，but aliens could answer our messages. 3. They hope one day they would be picked up by aliens' technology. These scientists want to prove that we are not alone in the universe.
4. Should we answer it? Stephen Hawking，the famous physicist，thought it could be dangerous to connect with aliens. He said the main purpose of aliens' visit to the Earth could be searching for our resources.
5. David Morrison，a NASA scientist，said，“If alien radio signal reaches the Earth from a planet thousands of light years away，then they almost surely have solved all the problems we still have including the shortage of resources. Maybe they are much smarter than us，but why do they want to hurt us? I think we can try to connect with them.”

1~5. BADEC