六級真題:2011年12月六級聽力真題-復(fù)合聽寫

In the past, one of the biggest disadvantages of machines has been their inability to work on a micro scale. For example, doctors did not have devices allowing them to go inside the human body to detect health problems or to perform delicate surgery. Repair crews 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 allows scientists to envision and in some cases actually build microscopic machines. These devices promise to dramatically change the way we live and work. Micromachines already are making an impact. At Case Western Reserve University in Cleveland, Ohio, research scientists have designed a 4-inch silicon chip that holds 700 tiny primitive motors. At Lucas Nova Sensor in Fremont, California, scientists have perfected the world's first microscopic blood-pressure sensor. Threaded through a person's blood vessels, the sensor can provide blood pressure readings at the valve of the heart itself. Although simple versions of miniature devices have had an impact, advanced versions are still several years away. Auto manufacturers, for example, are trying to use tiny devices that can sense when to release an airbag and how to keep engines and breaks operating efficiently. Some futurists envision nanotechnology also being used to explore the deep sea in small submarine, or even to launch finger-sized rockets packed with micro miniature instruments. "There is an explosion of new ideas and applications," So, when scientists now think about future machines doing large and complex tasks, they're thinking smaller than ever before.