[单项选择] Since the first brain scanner was constructed several years ago, computed tomography (X 线断层摄影术)or computed medical imagery, has become fairly widely used. Its rapid acceptance is due to the fact that it has overcome several of the drawbacks of conventional X-ray technology. To begin with, conventional two-dimensional X-ray pictures cannot show all of the information contained in a three-dimensional object. Things at different depths are superimposed, causing confusion to the viewer. Computed tomography can give three-dimensional information. The computer is able to re- construct pictures of the body’’s interior by measuring the varying intensities of X-ray beams passing through sections of the body from hundreds of different angles. Such pictures are based on series of thin ’’slices’’. In addition, conventional X-rays generally differentiate only between bone and air, as in the chest and lungs. They cannot distinguish .soft tissues or variations in tissues. The liver and pan
A. Two-dimensional.
B. Three-dimensional.
C. Animated.
D. Intensified.

[单项选择] Since the first brain scanner was constructed several years ago, computed tomography (X 线断层摄影术)or computed medical imagery, has become fairly widely used. Its rapid acceptance is due to the fact that it has overcome several of the drawbacks of conventional X-ray technology. To begin with, conventional two-dimensional X-ray pictures cannot show all of the information contained in a three-dimensional object. Things at different depths are superimposed, causing confusion to the viewer. Computed tomography can give three-dimensional information. The computer is able to re- construct pictures of the body’’s interior by measuring the varying intensities of X-ray beams passing through sections of the body from hundreds of different angles. Such pictures are based on series of thin ’’slices’’. In addition, conventional X-rays generally differentiate only between bone and air, as in the chest and lungs. They cannot distinguish .soft tissues or variations in tissues. The liver and pan
A. bone and air
B. liver and pancreas
C. muscle and other body
D. heart and lungs

[单项选择]

Since the late 1970’s, in the face of a severe loss of market share in dozens of industries, manufacturers in the United States have been trying to improve productivity and therefore enhance their international competitiveness through costcutting programs. (Cost-cutting here is definding the amount of labor constant.) However, from 1978 through 1982, productivity-- the value of goods manufactured divided by the amount of labor input-- did not improve; and while the results were better in the business upturn of the three years following, they ran 25 percent lower than productivity improvements during earlier, post-1945 upturns. At the same, it became clear that the harder manufactures worked to implement costcutting, the more they lost their competitive edge. With this paradox in mind, I recently visited 25 companies; it became dear to me that the costcutting approach to increasing productivity is fundamentally flawed. Manufacturing regularly observes a" 40, 40,20"
A. summarizing a thesis
B. recommending a different approach
C. comparing points of view
D. making a series of predictions

[单项选择]

Men have traveled ever since they first appeared on the earth.
In primitive times they did not travel for pleasure but to find new places where their herds could feed, or to escape from hostile neighbors, or to find more favorable climates. They traveled on foot. Their journeys were long, tiring, and often dangerous. They protected themselves with simple weapons, such as wooden sticks or stone clubs, and by lighting fires at night and, above all, by keeping together.
Being intelligent and creative, they soon discovered easier ways of traveling. They rode on the backs of their domesticated animals; they hollowed out tree trunks and, by using bits of wood as paddles, were able to travel across water.
Later they traveled, not from necessity, but for the joy and excitement of seeing and experiencing new things. This is still the main reason why we travel today.
Traveling, of course, has now become a highly organized business. There are cars and splendi
A. talkative
B. hot-headed
C. enthusiastic
D. unfriendly