求一篇完形填空的答案(最好能翻译一遍)

求一篇完形填空的答案(最好能翻译一遍)
Important steps have been taken since 1974 toward finding major applications for optical fibers in communications. The use of radio optics for communication through the __1__ and in space will continue to grow in importance, __2__ the prospect of development of space systems and technology, __3__ the prospect of developing light-wave communications systems to compete __4__ and expand traditional communication services __5__ shifted the emphasis toward the use of light-wave guiding fillers. Experimental optical-fiber __6__ systems are already in __7__ in some of the telephone systems in a few countries. The success of industry __8__ turning such effective techniques to __9__ by developing low-cost products will determine the impact which optical fibers have __10__ communications.
The telephone system can be __11__ into three networks: the local network, which ties customers to their __12__ local switching offices; the trunk network, which interconnects the switching offices; and the long-distance network between cities. Local lines, __13__ called loops(环行路线), tie customers to switching offices almost on a one-to-one __14__ ; large, relatively short groups of lines tie the switching offices together; and __15__ larger and much longer groups of lines interconnect cities. Even though optical fibers are much __16__ than wire pairs, and silica (the cost widely used material in fibers) is vastly more __17__ than copper, the cost of preparing the rods from __18__ optical fibers are drawn is several times greater than the cost of producing wires. __19__, studies suggest that this may be the __20__ for some time.
1.A.cloud B.fog C.atmosphere D.wind
2.A.specially B.particularly C.specifically D.universally
3.A.but B.and C.or D.so
4.A.in B.for C.to D.with
5.A.are B.is C.have D.has
6.A.transportation B.transition C.transit D.transmission
7.A.line B.progress C.use D.hand
8.A.about B.at C.in D.of
9.A.advantage B.profit C.benefit D.interest
10.A.on B.in C.into D.to
11.A.divided B.translated C.changed D.turned
12.A.respectable B.respective C.respectful D.respected
13.A.abstractly B.concretely C.politically D.traditionally
14.A.base B.foundation C.basis D.ground
15.A.quite B.even C.fairly D.very
16.A.bigger B.smaller C.shorter D.longer
17.A.ample B.abundant C.sufficient D.adequate
18.A.what B.how C.where D.which
19.A.Moreover B.Instead C.Consequently D.Conversely
20.A.situation B.truth C.case D.point

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