gre写作辅导：写作资料句子21

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4. 微型机器
In the past, one of the biggest disadvantages of machines has been their inability to work on a micro (or tiny) scale. For example, doctors did not have devices allowing them to go inside the human body to identify health problems to perform delicate surgery. Repair crew did not have a way of identifying broken pipes located deep within a high-rise apartment building. However, that’s about to change. Advances in computers and biophysics have started a micro miniature revolution that’s allowing scientists to envision and in some cases actually build microscopic machines. These devices promise to radically change the way we live and work.

5. 环境压力
7 o* o1 d1 Y6 F6 f*New technologies often cause new forms of pollution and environmental stress. Pollution may be defined as the addition to the environment of agents that are potentially damaging to the welfare of humans or other organisms. Environmental stress is a more general term that refers to effects of society on the natural environment. Pollution is the most common form of environmental stress, but it is not the only one.
+ v. P: a1 ]$ QOne example of environmental stress resulting from technology is the surprising finding that winter fish kills in Wisconsin lakes were caused by snowmobiles. Heavy snowmobile ues on a lake compacts the snow, thereby reducing the amount of sunlight filtering through the ice and interfering with photosynthesis by aquatic plants. As the plant life dies, its decomposition further reduces the amount of oxygen in the water. The fish then die of asphyxiation.
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In sum, although scientific discoveries and technological advances have produced tremendous improvements in the quality of human life, they have often had negative consequences as well. The risk of cancer caused by the inhalation of asbestos particles, the possibility of large-scale industrial accidents, the ethical issues raised by the use of life-prolong technologies, and the ever-present danger of nuclear holocaust are as much a part of the modern era as space travel, miracle drugs, and computers that can operate whole factories. Although technology is not “out of control’, there is clearly a need for improved procedures for anticipating and preventing the negative consequences of new technologies.