Sailors long ago were often afraid that if they sailed too far from home they would fall off the 1 of the flat ocean. In the 2 , many people had to trust the words of 3 , for they had no way to gather 4 for themselves. Today, we can fly in airplanes high over the 5 and see the curve（曲线）that is proof of its roundness. Astronauts flying miles high can send us 6 that support our beliefs. Most people now 7 the fact that the earth is certainly not flat. 8 many of them don't realize that it's not exactly 9 either.
A mathematician, Ann Eckels Bailie, used computers to gather information to 10 in planning space flights.
During 11 work of tracking the second U. S. satellite, Vanguard I, she discovered some facts that didn't 12 to make sense （讲得通）. It appeared that the perigee (or point nearest to the earth) satellite orbit （轨道）measured a different 13 from the northern hemisphere（半球） of our earth than from the 14 hemisphere. At first, she thought this strange 15 were because of some mathematical mistakes. But Bailie wouldn't 16 the idea that important new information had been 17 . She and other scientists discussed the 18 of the earth again. 19 research finally proved that Bailie's 20 finding was correct.
1．A．bottom B．edge C．top D．water
2．A．end B．future C．beginning D．past
3．A．others B．gods C．anybody D．theirs
4．A．advice B．help C．information D．announcements
5．A．earth B．star C．moon D．universe
6．A．news B．sounds C．gifts D．pictures
7．A．refuse B．proves C．accept D．find
8．A．But B．And C．So D．Therefore
9．A．smooth B．natural C．round D．still
10．A．sell B．use C．enjoy D．store
11．A．her B．his C．its D．our
12．A．want B．like C．seem D．help
13．A．distance B．size C．weight D．length
14．A．any B．another C．eastern D．southern
15．A．materials B．figures C．problems D．answers
16．A．go over B．get in C．give up D．put out
17．A．discovered B．invented C．formed D．received
18．A．history B．position C．route D．shape
19．A．No more B．Further C．Happy D．Difficult
20．A．useless B．frightening C．accidental D．usual
答案与提示：
1．B 担心会从“边缘”滑下，因为他们不知道地球是圆的，总以为它一定有其尽头。
2．D 与后面的today形成对比，A、C表意不清，B不合文意。
3．A 由于后一分句所述的原因，他们只得相信“他人”的话，余者不合常识和逻辑。
4．C C与A、D相比内涵更加丰富，A、D不能完整地表达这里的意思，另B表意不清。
5．A 飞机只能在“地球”的上空飞行，余者不合常识。
6．D 根据常识可以判断出。
7．C 由下一句以及文章首句可以推知。
8．A 与前句形成对比。
9．C 由下文可知，除少数科学家外，大多数人都以为地球是完全“圆”的。
10．B 将信息“用”在设计太空飞行上。
11．A 由句子的主语she可以推知。
12．C 由It appeared that…。
13．A 测量的是卫星近地点到南北半球之间的“距离”。
14．D 由northern hemisphere推知。
15．B figure指所测量出的“数据”。
16．C
17．A 但是，她不愿“放弃”已“发现”新的重要信息这一念头。
18．D 要证明她想法的正确性，就得反复研究其“形状”。
19．B “进一步的”研究证明……A不合语境应排除；研究的具体情形文中末涉及，故C、D亦应舍去。
20．C 她是在跟踪卫星的过程中发现上述事实的。因此，这一发现颇具偶然性。
