试题库在线考试题库-历年真题模拟试题及答案-考博英语在线试题测试中心-希赛网

南开大学

Complete silence is found only in laboratories called anechoic rooms. The walls and ceilings, made of blocks of special sound-sucking materials, are more than three feet thick, while floor coverings are six-foot layers of feathers or cotton wool. Silence here can be as painful to the ears as the din (continuous loud noise) of a steelworks or a rocket blast-off, yet scientists get used to this and stay in these silent rooms for hours at a time, using microphones and electronic equipment to test the various materials being developed to make the world a less noisy place.Architects have used scientific discoveries to solve noise problem in a number of ways. Walls are hollowed (having empty space inside) and then filled with sound-sucking materials similar to cotton wool. Extra-thick carpets cover the floors, and thick woolen curtains cover the windows. Air conditioning and heating channels are made less noisy by sound-sucking materials．Unfortunately, these techniques and others often work too well in some buildings. Noise-proof rooms become almost anechoic and people living in them are disturbed by the lack of sound．One way of handling this problem is to use what they call “sound perfume” — artificial (similarly produced, made by man) noise is piped to rooms through small loudspeakers.1.Scientists use anechoic room for（） .2.The writer implies that （） .3.People suffer in anechoic rooms probably because （） .4.The article suggests that （） .

An unidentified wit once said, “laugh, and the world laughs with you. Snore, and you sleep alone.” Yet snoring is far from a laughing matter, as those unfortunates with good hearing, who are rightly subjected to the sounds of the snoring disorder, will testify.It has been estimated that one of eight Americans snores: this means that there are approximately 21 million people—women as well as men—who render an unpleasant sound when they are asleep. And assuming that each snorer disturbs the sleep of at least one other person, it necessarily follows that there are 21 million unhappy listeners. While a sleeping person breathes, either in or out, several structures in his nose and throat generate the snoring. The sounds, coming from the soft palate and other soft structures of the throat, are caused by vibratory responses to inflowing and outflowing air. When the soft tissues of the mouth and throat come close to the lining of the throat, the vibrations that occur are caused by the position of the tongue. In short, the noise made by snoring can be compared to the noise when breezes flutter a flag on a pole. The frequency of the vibrations depends on the size, density, and elasticity of the affected tissues and on the force of the air flow. Although it is usually the process of in haling or exhaling through the mouth that cause snoring, short snorts come from the nose of an open-mouthed sleeper. In all fairness to snorers, however, it should be emphasized that snoring is an involuntary out which stops as the offender is awakened.1.The snoring is caused by （） .2.If a person produces short snores, most probably he has （） .3.The snorers can have control over their act.4.The author’s attitude towards the snorers is （） .

He soon regained his self-confidence for he found himself （） to others in many respects.

Although Venus is the nearest planet of the Earth, little is known about it because it is （） covered by thick clouds.

The doctor told me the medicine can （） my headache without doing me any harm.

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