Winged Robot Learns to Fly
　　 Learning how to fly took nature millions of years of trial and error—but a winged robot has cracked it in only a few hours, using the same evolutionary principles.
　　 Krister Wolff and Peter Nordin of Chalmers University of Technology (CUT) in Gothenburg, Sweden, built a winged robot and set about testing whether it could learn to fly by itself, without any pre-programmed data on what flapping is or how to do it.
　　 To begin with, the robot just twitched and jerked erratically. But, gradually, it made movements that gained height. At first , it cheated — simply standing on its wing tips was one early short cut. After three hours, however, the robot abandoned such methods in favor of a more effective flapping technique, where it rotated its wings through 90 degrees and raised them before twisting them back to the horizontal and pushing down.
　　 “This tells us that this kind of evolution is capable of coming up with flying motion,” says Peter Bentley, who works on evolutionary computing at University College London. But while the robot had worked out how best to produce lift, it was not about to take off. “There’s only so much that evolution can do, Bentley says. This thing is never going to fly because the motors will never have the strength to do it,” he says.
　　 The robot had metre-long wings made from balsa wood and covered with a light plastic film. Small motors on the robot let it move its wings forwards or backwards, up or down or twist them in either direction.
　　 The team attached the robot to two vertical rods, so it could slide up and down. At the start of a test, the robot was suspended by an elastic band. A movement detector measured how much lift, if any, the robot produced for any given movement.
　　 A computer program fed the robot random instructions, at the rate of 20 per second, to test its flapping abilities. Each instruction told the robot either to do nothing or to move the wings slightly in the various directions.
　　 Feedback from the movement detector let the program work out which sets of instructions were best at producing lift. The most successful ones were paired up and “offspring” sets of instructions were generated by swapping instructions randomly between successful pairs. These next-generation instructions were then sent to the robot and evaluated before breeding a new generation, and the process was repeated.
1.Which of the following is NOT true of what is mentioned about the winged robot in the second paragraph?
A. The two professors of CUT built the winged robot.
B. The two professors of CUT tested whether the winged robot could learn to fly.
C. The two professors of CUT programmed the data on how the robot flapped its wings.
D. The two professors of CUT tried to find out if the robot could fly by itself.

2.How did the robot behave at the beginning of the test?
A. It rotated its wings through 90 degrees.
B. It twitched but gradually gained height.
C. It was twitched and broke down.
D. It landed not long after the test.

3.Which of the following is nearest to Peter Bentley’s view on the winged robot?
A. The winged robot could never really fly.
B. The winged robot did not have a mortor.
C. The winged robot should go through further evolution before it could fly.
D. The robot could fly if it were lighter.

4.What measured how much lift the robot produced?
A. Two vertical rods.
B. A movement detector.
C. An elastic band.
D. Both B and C.

5.What does “the process” appearing in the last paragraph refer to?
A. Pairing up successful instructions.
B. Sending instructions to the robot.
C. Generating new sets of instructions for evaluation.
D. All the above.

Stress level Tied to Education Level
　　 People with less education suffer fewer stressful days, according to a report in the current issue of the Journal of Health and Social Behavior.
　　 However, the study also found that when less-educated people did suffer stress it was more severe and had a larger impact on their health.
　　 From this, researchers have concluded that the day-to-day factors that cause stress are not random, Where you are in society determines the kinds of problems that you have each day, and how well you will cope with them.
The research team interviewed a national sample of 1,031 adults daily for eight days about their stress level and health. People without a high school diploma reported stress on 30 percent of the study days, people with a high school degree reported stress 38 percent of the time, and people with college degrees reported stress 44 percent of the time.
　　 “Less advantaged people are less healthy on a daily basis and are more likely to have downward turns in their health,” lead researcher Dr Joseph Grzywacz, of Wake Forest University Baptist Medical Center, said in a prepared statement. “The downward turns in health were connected with daily stressors, and the effect of daily stressors on their health is much more devastating for the less advantaged.”
　　 Grzywacz suggested follow-up research to determine why less-educated people report fewer days of stress when it is known their stress is more acute and chronic.
　　 “If something happens every day, maybe it’s not seen as a stressor,” Grzywacz says. “Maybe it is just life.”
1.Stress level is closely related to
A. family size.
B. social status.
C. body weight.
D. work experience.

2.The 1,031 adults were interviewed
A. on a daily basis for 8 days.
B. during one of eight days.
C. all by Grzywacz.
D. in groups.

3.Which group reported the biggest number of stressful days?
A. People without any education.
B. People without high school degrees.
C. People with high school degrees.
D. People with college degrees.

4. The less advantaged people are, the greater
A. the impact of stress on their health is.
B. the effect of education on their health is.
C. the level of their education is.
D. the degree of their health concern is .

5.Less educated people report fewer days of stress possibly because
A. they don’t want to tell the truch.
B. they don’t want to face the truth.
C. stress is too common a factor in their life.
D. their stress is more acute.