The sensation of sound involves a variety of factors in addition to its peak level. Advertisers are skilful at creating the impression of loudness through their expert use of such factors. One major contributor to the perceived loudness of commercials is that much less variation in sound level occurs during a commercial. In regular programming the intensity of sound varies over a large range. However, sound levels in commercials tend to stay at or near peak levels.
Other "tricks of the trade" are also used. Because low-frequency sounds can mask higher frequency sounds, advertisers filter out any noises that may drown out the primary message. In addition, the human voice has more auditory(听觉的) impact in the middle frequency ranges. Advertisers electronically vary voice sounds so that they stay within such a frequency band. Another approach is to write the script. so that lots of consonants(辅音) are used, because people are more aware of consonants than vowel(元音) sounds. Finally, advertisers try to begin commercials with sounds that are highly different from those of the programming within which the commercial is buried. Because people become adapted to the type of sounds coming from programming, a dramatic change in sound quality draws viewer attention. For example, notice how many commercials begin with a cheerful song of some type.
The attention-getting property of commercials can be seen by observing one-to-two-year-old children who happen to be playing around a television set. They may totally ignore the programming. However, when a commercial comes on, their attention is immediately drawn to it because of its dramatic sound quality.
According to the passage, the maximum intensity of sound coming from commercials ______.
A.does not exceed that of programs
B.is greater than that of programs
C.varies over a large range than that of programs
D.is less than that of programs
第2题
有机磷农药中毒的发病机制
A、抑制胆碱酯酶活力
B、碳氧血红蛋白蓄积
C、高铁血红蛋白蓄积
D、交感神经过度兴奋
E、迷走神经过度兴奋
第3题
有机磷农药中毒的发病机制()
A.抑制胆碱酯酶
B.碳氧血红蛋白蓄积
C.高铁血红蛋白蓄积
D.交感神经过度兴奋
E.迷走神经过度兴奋
第5题
有机磷农药中毒的发病机理是()
A.迷走神经过度兴奋
B.交感神经过度兴奋
C.抑制胆碱酯酶
D.碳氧血红蛋白蓄积
E.高铁血红蛋白蓄积
第6题
有机磷农药中毒的发病机理是()
A.迷走神经过度兴奋
B.交感神经过度兴奋
C.抑制胆碱酯酶
D.碳氧血红蛋白蓄积
E.高铁血红蛋白蓄积
第7题
有机磷农药中毒的机制是
A.胆碱酯酶活性受抑制
B.碳氧血红蛋白在体内蓄积
C.高铁血红蛋白在体内蓄积
D.交感神经过度兴奋
E.迷走神经过度兴奋
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