题目

阅读表达阅读下面的短文和问题，根据短文内容，在相应题号后的横线上写下相关信息（不多于五个单词），完成对该问题的回答。     Sound is very important in our daily lives. Most of us get information and know what's happening around us by the sounds we hear. We talk with other people and listen to radio and television broadcasts for music, news, and enjoyment. Sound can be useful and pleasing or it can be unpleasant, and damaging to our ears. Unwanted, harmful sounds are called noise pollution.     The movements of people, animals, machines, and other things cause pressure waves in the air. If these pressure waves are within a certain range(范围)of frequencies(频率), our ears believe that it is sound. Sound waves are like the waves in a lake when you throw a stone. The bigger the stone, the bigger the waves. And that's how sound works. Big sounds cause larger waves.     Scientists measure these sound waves in decibels. To be heard by humans, a sound wave must measure at least ten decibels. When these waves reach a high number of decibels, our ears start to hurt and damage can occur. If you've been around loud noises for several hours, you may have experienced damage. It's important to know the danger signal: ringing in your ears.     Keep your ears safe-be careful what you hear! （1） What is noise pollution? （2） What may damage our ears? （3） What is the passage mainly about? 答案： Unwanted, harmful sounds. Loud noises Noise pollution and its danger./Noise pollution.

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