【单选题】

Television was not invented by any one person. Nor did it spring into being overnight. It evolved gradually, over a long period, from the ideas of many people -- each one building on the work of their predecessors. The process began in 1873, when it was accidentally discovered that the electrical resistance of the element selenium varied in proportion to the intensity of the light shining on it. Scientists quickly recognized that this provided a way of transforming light variations into electrical signals. Almost immediately a number of schemes were proposed for sending pictures by wire(it was, of course, before radio). 

One of the earliest of these schemes was patterned on the human eye. Suggested by G. R. Carey in 1875, it envisioned a mosaic of selenium calls on which the picture to be transmitted would be focused by a lens system. At the receiving end there would be a similarly arranged mosaic made up of electric lights. Each selenium cell would be connected by an individual wire to the similarly placed light in the receiving mosaic. Light falling on the selenium cell would reproduce the original picture, had the necessary amplifiers and the right kind of lights been availablr, this system would have workrd. But it also would have required an imoractical number of connecting wires. Carey recognized this and in a second proposed to “scan” the cells-transmitting the signal from each cell to its associated light, in turn, over a single wire. If this were done fast enough, the retentive power of the eye would cause the resultant image to be seen as a complete picture.
41. Which of the following is the best title for the passage?
A. Television in the Electronic Era
B. First Steps in the Invention of Television
C. The Art of Television
D. Harmful Effects of Television Viewing
42. In line 1, the word “being” could best be replaced by _____.
A. place
B. creature
C. subsistence
D. existence
43. An important discovery in earlyteleviosion was the electrical resistance of _____.
A. mosaics
B. the human eye
C. lenses
D. the element selenium
44. In 1875, Carey suggested that the human eye envisioned a mosaic of selenium cells on which the picture to be transmitted would be focused by ______.
A. wire
B. electric lights
C. a lens system
D. amplifiers
45. Following are the reasons why the first scheme for television was abandoned except _____.
A. he lacks an effective assistant
B. the necessary amplifers were unavailable
C. the proper lights were unavailable
D. the number of connecting wires is impractical