31.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.

　　注：文章第一段no difference

　　32.Commercials create the sensation of loudness because _______ .

　　A) TV stations always operate at the highest sound levels.

　　B) their sound levels are kept around peak levels.

　　C) their sound levels are kept in the middle frequency ranges.

　　D) unlike regular programs their intensity of sound varies over a wide range.

　　注：第二點(diǎn)

　　33.Many commercials begin with a cheerful song of some kind because ________ .

　　A) pop songs attract viewer attention.

　　B) it can increase their loudness.

　　C) advertisers want to make them sound different from regular programs.

　　D) advertisers want to merge music with commercials.

　　注：第四點(diǎn)

　　34.One of the reasons why commercials are able to attract viewer attention is that ________ .

　　A) the human voices in commercials have more auditory impact.

　　B) people like cheerful songs that change dramatically in sound quality.

　　C) high-frequency sounds are used to mask sounds that drown out the primary message.

　　D) they possess sound qualities that make the viewer feel that something unusual is

　　happening.

　　注：第三段Because，B選項(xiàng)like太主觀。

　　35.In the passage, the author is trying to tell us ________ .

　　A) how TV ads vary vocal sounds to attract attention.

　　B) how the loudness of TV ads is overcome.

　　C) how advertisers control the sound properties of TV ads.

　　D) how the attention-getting properties of sounds are made use of in TV ads.

　　注：文章最后一段