In these days of technological triumphs, it is well to remind ourselves from time to time that living mechanisms are often incomparably more efficient than their artificial imitations. There is no better illustration of this idea than the sonar system of bats. Ounce for ounce and watt for watt, it is billions of times more efficient and more sensitive than the radars and sonars designed by man. Of course, the bats have had some 50 million years of evolution to refine their sonar. Their physiological mechanisms for echo location, based on all this accumulated experience, therefore merit our thorough study and analysis. To appreciate the precision of the bats' echo location, we must first consider The degree of their reliance upon it. Thanks to sonar, an insect-eating bat can get along perfectly well without eyesight. This was brilliantly demonstrated by an experiment performed in the late eighteenth century by the Italian naturalist Lazure Spallanzani. He caught some bats in a bell tower, blinded them, and released them outdoors. Four of these blind bats were recaptured after they had found their way back to the bell tower, and on examining their stomachs' contents, Spallanzani found that they had been able to capture and fill themselves with flying insects. We know from experiments that bats easily find insects in the dark of night, even when the insects emit no sound that can be heard by human ears. A bat will catch hundreds of soft-bodied, silent-flying moths in a single hour. It will even detect and chase pebbles tossed into the air.

　　1. The passage is mainly about _____.

　　[A] living mechanisms and their artificial imitations

　　[B] the remarkable sonar system of bats

　　[C] the deficiencies of man-made sonars

　　[D] the experiment of "blind-bats"

　　2. Where of the following statements is true?

　　[A] Living mechanisms are always more efficient than their artificial imitations.

　　[B] Bats rely on their sonar system as well as eyesight to eat insects.

　　[C] The sonar system of bats has had 50 million years to be refined.

　　[D] People have discovered the bats' sonar system thousands of years age.

　　3. Lazzoro Spallanzani demonstrated that a bat can get along well without eyesight through _____.

　　[A] He caught soem bats and blinded them and released them.

　　[B] Four of these blind bats found their way back.

　　[C] He recaptured the four returned bats.

　　[D] The stomachs' of the blind bats found to be fill with flying insects.

　　4. Bats find insects in the dark of night with the help of _____.

　　[A] echoesＷww.KaＯ8.CC

　　[B] eyesight

　　[C] sound waves

　　[D] none ofthe above

　　5 Implied but not stated _____.

　　[A] Pebbles tossed into the air make no sound that can be heard by human ears

　　[B] A bat will catch hundreds of months in a single hour

　　[C] Insect-eating bats are totally blind

　　[D] The sonar system of bats is as good as man-made sonar

　　参考答案：B C D D A

　　The kind of music, song, and dance a people generates, with its characteristic rhythm and beat, forms one of the best indexes of its cultural style, and in America, the dominant musical styles are blues, swing and jazz. The lyrics to this music are often foolishly sentimental and sometimes non-sensical, but frequently they embody a wild and earthy humor, or a sad and tragic strain. As distinguished from most American popular tunes, American hot music is not written to be danced to. Yet there is an internal beat in jazz which relates deeply to dance: the movements of the body interpret the music's intent better than words can. When there is dancing, however, the dances break away from a formal pattern and, at their bat, keep with the improvisation (即兴) of the music. Unlike earlier American folk dances, which are collective, so-called ballroom dancing is performed by couples. Each couple is comparatively alone, not being well enough acquainted with the other couples on the dance floor to join them. But, in the swing dancing, as the music mounts the partners separate to execute complicated solo variations and then rejoin each other. As the music approaches one of its climaxes, the dancers pay the musicians the tribute(赞美) of gathering around to cheer them on. In popular dance and music, Americans come closer to reaching a native idiom of religious feeling than they do in any other aspect of their lives.

　　1. The main idea of the passage is that _____.

　　[A] popular dance and music are an important aspect of American life

　　[B] the American hot music is different from most American popular tunes

　　[C] modern dancing is different from earlier American folk dances

　　[D] all of the above

　　2. The difference between American hot music and most American popular tunes is that _____.

　　[A] the lyrics to hot music are nonsensical

　　[B] most American popular tunes are written to be danced to

　　[C] there is not internal beat in hot music

　　[D] hot music can not be interpreted by dance

　　3. According to the passage,the swing dancing _____.

　　[A] collective

　　[B] performed by couples

　　[C] individual improvising

　　[D] gathering around the musician

　　4. Which is the relationship between jazz and dance?

　　[A] Both the music and the dance have formal pattern.

　　[B] The dances always keep the music to interpret it.

　　[C] Jazz has nothing to do with dance.

　　[D] Jazz can be interpreted by dance,though not so well as by words.

　　5. In the swing dancing,the musicians _____.

　　[A] cheer the dancers on

　　[B] gather around the dancers

　　[C] execute complicated variations

　　[D] were gathered around by the dancers

　　参考答案：A B C D B