問題詳情


(B) Until the middle of the 1960’s, copper had been the material of choice for telephone communicationsbecause it is a good conductor of electricity, is flexible, and can be produced relatively inexpensively. In 1996,however, two scientists working in England, K.C. Kao and G.H. Hockham, suggested that transmission ofinformation by copper wire my not be the most efficient and cost-effective method possible. They __26__ thatfibers—long, thin, hollow tubes resembling a fine strand of hair—might be developed to replace copper wiring.Over the course of the next twenty years, fiber optic cables began to replace __27__ metallic wiring. The problem with copper wiring is loss of electrical signal over great distances, or attenuation. __28__attenuation can be controlled and somewhat alleviated by boosting the signal over intervals, this solution ishardly an ideal one. An electrical signal requires a boost every 1.5 kilometers. On the other hand, fiber opticcables transmit laser light rather than electricity. The inner lining of the hollow fiber optic cable is coated with ahighly reflective substance. Thus, instead of escaping through the walls of the fiber, the laser light is bouncedback off the walls and into the center of the fiber. __29__, attenuation is lessened to the point of virtualelimination, which means that a fiber optic signal needs a boost only every 100 kilometers. While most oftencomposed of glass, fibers can also be made of plastics, though with a somewhat lesser degree of conductiveefficiency. Although the most widespread use of fiber optics is in the communication sector, the technology has alsohad an impact on the medical field. Bundles of fiber optic cables are now used by surgeons both as sources oflight and as cameras. __30__, fiber optic camera techniques have replaced a good portion of exploratory surgerythat had previously been necessary for the assessment of internal illnesses.
26.
(A) postulated
(B) rummaged
(C) interposed
(D) capsized

參考答案

答案：A
難度：適中0.5
統計：A(0),B(0),C(0),D(0),E(0)

內容推薦

內容推薦