Passage Two

A scientist once said: “I have concluded that the earth is being visited by intelligently controlled vehicles from outer space.”

If we take this as a reasonable explanation for UFOs (unidentified flying objects), questions immediately come up. “Why don’t they get in touch with us, then? Why don’t they land right on the White House lawn and declare themselves?” people asked. In reply, scientists say that, while this may be what we want, it may not necessarily be what they want.

“The most likely explanation, it seems to me,” said Dr. Mead, “is that they are simply watching what we are up to---that responsible society outside our solar system is keeping an eye on us to see that we don’t set in motion a chain reaction that might have unexpected effects for outside our solar system.”

Opinions from other scientists might go like this: “Why should they want to get in touch with us? We may feel we’re more important than we really are! They may want to observe us only and not interfere with the development of our civilization. They may not care if we see them but they also may not care to say hello.”

Some scientists have also suggested that Earth is a kind of zoo or wildlife reserve. Just as we set aside wilderness areas and wildlife reserves to allow animals and growing things to develop naturally while we observe them, perhaps Earth was set aside ages ago for the same purpose.

Are we being observed by intelligent beings from other civilizations in the universe? Are they watching our progress in space travel? Do we live in a gigantic “zoo” observed by our “keepers”, but having no communication with them?

Now we have to recognize that, among the stars in the heavens, there may very well be worlds inhabited by beings who arc to us as we arc to ants.

26. People who ask the question “Why don’t they get in touch with us... and declare themselves?” may have thought that ______.

A. there are no such things as UFOs

B. UFOs are visitors from solar system

C. there’s no reason for UFOs sooner or later

D. we are bound to see UFOs sooner or later

27. According to Dr. Mead, the attitude of beings from outer space toward us is one of ______.

A. unfriendliness                                                  B. suspicion

C. superiority                                                      D. hostility

28. In line 21, the word “keepers” refers to ______.

A. persons who look after animals in a gigantic zoo

B. astronauts travelling in the manned space ship

C. persons who are observing us

D. intelligent beings observing us from outer space

29. The writer thinks that ______.

A. in the heavens there may be other worlds inhabited by intelligent beings

B. human beings are as supreme as the intelligent beings in outer space

C. maybe human beings are not so supreme as the beings from other civilizations in the universe

D. the beings from other civilizations in the universe will come to meet us and say hello one day

30. The tone of the writer is that of ______.

A. doubt                                                             B. warning

C. indifference                                                    D. criticism