阅读理解。
Believe it or not, optical illusion (错觉) can cut highway crashes.
Japan is a case in point. It has reduced automobile crashes on some roads by nearly 75 percent
using a simple optical illusion. But stripes, called chevrons (人字形), painted on the roads make drivers
think that they are driving faster than they really are, and thus drivers slow down. Now the American
Automobile Association Foundation for Traffic Safety in Washington D.C. is planning to repeat
Japan's success. Starting next year, the foundation will paint chevrons and other patterns of stripes
on selected roads around the country to test how well the patterns reduce highway crashes.
Excessive (too great) speed plays a major role in as much as one fifth of all fatal traffic accidents,
according to the foundation. To help reduce those accidents, the foundation will conduct its tests in
areas where speed-related hazards (danger) are the greatest curves, exit slopes, traffic circles, and bridges.
Some studies suggest that straight, horizontal bars painted across roads can initially cut the average speed
of drivers in half. However, traffic often returns to full speed within months as drivers become used to
seeing the painted bars.
Chevrons, scientists say, not only give drivers the impression that they are driving faster than they
really are but also make a lane appear to be narrower. The result is a longer lasting reduction in highway
speed and the number of traffic accidents.
1. The passage mainly discusses _______.
A. a new way of highway speed control
B. a new pattern for painting highways
C. a new way of training drivers
D. a new type of optical illusion
2. On roads painted with chevrons, drivers tend to feel that _______.
A. they should avoid speed-related hazards
B. they are driving in the wrong lane
C. they should slow down their speed
D. they are coming near to the speed limit
3. The advantage of chevrons over straight, horizontal bars is that the former _______.
A. can keep drivers awake
B. can cut road accidents in half
C. will look more attractive
D. will have a longer effect on drivers
4. The American Automobile Association Foundation for Traffic Safety plans to _______.
A. try out the Japanese method in certain areas
B. change the road signs across the country
C. replace straight, horizontal bars with chevrons
D. repeat the Japanese road patterns
=
x=5.55g
y=2.2g………………………………（1分）
×100%=14.1%………………（1分）
×100%即可求得反应后所得溶液的溶质质量分数．