Sixty years ago

共享题干题根据短文的内容，回答下列题目
     UFOs
     Sixty years ago, a man named Kenneth Arnold saw something that we can still __________ (51)today-- something that changed popular culture for ever.
Flying his plane over mountains in the US state of Washington, he saw a line of strange objects, either crescent-shaped ( 月牙形的 ) or disc-like, flying __________ (52) the motion of a saucer (碟) skimming (飞速掠过) on water.
     The media soon picked up on the story--the Flying Saucers were here! Was the earth being__________ (53) by creatures from another planet? Soon, So many sightings were made that the US military began to __________ (54). It called these strange Objects UFOs--Unidentified Flying Objects, and that is how they are __________ (55)today. Military investigations found no evidence of visitors from outer space. But that did not stop the true __________ (56). The military were __________ (57) up, they said. Or maybe it was because the travelers from space were of such superior intelligence __________ (58) they could hide from military analysts (分析家) .
     People have always seen strange lights in the sky. In the past these were explained in __________ (59)ways. In a world where religion was less infuenfial and science fiction was popular, signs from God were replaced by visitors from other __________ (60).
     The date of the first UFO sightings was also significant. In 1947, World War I! had just ended and the __________ (61) War was just beginning. Humanity seemed locked in endless conflicts.
     Like generations before them, people looked __________ (62) the skies for help. But instead of seeking God, they looked for help from super-intelligent aliens (外星人) with __________ (63)technology. Belief in UFOs became the first religion of science.
     However, even people who believe in UFOs are not quite sure why they visit the earth. The universe is a big place and it is __________ (64) to assume that there is life somewhere out there.
     It is possible that aliens have worked out how to travel through space. Yet some people report that they have been taken by aliens and have had experiments __________ (65) on them. Why would anyone travel across half the universe to conduct medical experiments on people living in small towns in the United States?