新东方名师推荐:四六级优秀范文背诵(4)

2010-09-04 00:00:00来源:新东方四六级

最后冲刺

2010年四六级备考手册:听力篇(更新中…)

2010年四六级备考手册:阅读篇(更新中…)

2010年四六级备考手册:写作篇(更新中…)

考前必备

四级写作高分工具:新概念3常见词汇句法

名师指导6月六级最后冲刺备考方法

四六级名师传授绝技:5个词拿下快速阅读

2010年6月六级听力考试场景词汇精要

六级听力长对话短期突破:从真题入手

2010年6月四六级考试真题答案点评
2010年6月四六级考试真题答案点评汇总


04 Electricity

The modern age is an age of electricity. People are so used to electric lights, radio, televisions, and telephones that it is hard to imagine what life would be like without them. When there is a power failure, people grope about in flickering candlelight, cars hesitate in the streets because there are no traffic lights to guide them, and food spoils in silent refrigerators.

Yet, people began to understand how electricity works only a little more than two centuries ago. Nature has apparently been experimenting in this field for million of years. Scientists are discovering more and more that the living world may hold many interesting secrets of electricity that could benefit humanity.

All living cell send out tiny pulses of electricity. As the heart beats, it sends out pulses of record; they form an electrocardiogram, which a doctor can study to determine how well the heart is working. The brain, too, sends out brain waves of electricity, which can be recorded in an electroencephalogram. The electric currents generated by most living cells are extremely small – often so small that sensitive instruments are needed to record them. But in some animals, certain muscle cells have become so specialized as electrical generators that they do not work as muscle cells at all. When large numbers of these cell are linked together, the effects can be astonishing.

The electric eel is an amazing storage battery. It can seed a jolt of as much as eight hundred volts of electricity through the water in which it live. ( An electric house current is only one hundred twenty volts.) As many as four-fifths of all the cells in the electric eel’s body are specialized for generating electricity, and the strength of the shock it can deliver corresponds roughly to length of its body.

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