Passage One
Nowadays more and more people have to spend lengthy hours before computers. Computers are almost indispensable to modern life. No one can imagine the results if the computer he uses daily would break down. [26]But computers also cause some problems. Among them is the potential harm to human bodies, especially to eyes.
Working long hours at a computer can cause eyestrain. Recently a letter to the New England Journal of Medicine provides one explanation for the problem. Japanese researchers studied some 50 office workers who spent an average of three hours a day at a terminal. [27]Since blinking keeps eyes moist-thus reducing strain-the researchers counted blinking rates under different conditions. The workers averaged 22 blinks a minute when relaxed, ten blinks a minute while reading a book and just seven a minute while reading text on a computer screen. Thus people keep the least moisture in their eyes when they are working at a computer and feel more strained. Furthermore, the computer workers also kept their eyes open wider, which meant moisture evaporated more quickly.
[28]If you work at a computer screen, close your eyes periodically. That spreads a tear film and rests your eyes. And remember to blink more often. In this way you can reduce the side effect caused by using computer to a greater extent.

答案解析：
26. What is the result of using computer in our daily life?
[A]解析：细节题。computer是人们日常生活、工作不可缺少的一部分，但短文同时指出，电脑也带来问题，其中一个就是可能给人的身体带来伤害。故A正确。BUT题，听到BUT就知道其后的内容需要格外重视。
27. What is the cause of eyestrain?
[D]解析：推断题。短文提到：“...blinking keeps eyes moist-thus reducing strain...”（眨眼使眼睛保持湿润，从而减少眼疲劳）；而短文还指出，使用电脑时人们的眨眼频率仅为每分钟7次，非常低，因此眼睛的湿润度很低，由此引起眼疲劳。故D正确。
28. What are those who spend long hours before computers supposed to do?
[C]解析：细节题。短文提到，如果你工作中面对电脑，应该经常性地闭眼休息。因此C正确。