单选题 Store shelves are filling up with so-called "green" products promising to benefit the environment. A recent controversy pitting the influential magazine Consume Reports against a popular new energy-saving device shows that it can be as difficult for buyers to confirm such claims as for manufacturers to defend them.
The controversy concerns the GreenPlug Electricity Saver ($29～$39 retail). Consumers snapped 500 000 in 1993, the plug's first year on the market. Gross revenue was $10 million for the fledgling manufacturer, Green Technologies Inc. , of Boulder, Colo.
The GreenPlug is supposed to prevent energy waste by appliances whose constant-speed motors operate at less than full load—as is especially true of older refrigerators. Research conducted for the space shuttle showed that such motors can be made to do the same work with less heat, noise, and power consumption just by lowering the voltage of the power supply.
John and Wyck Hay, two of the founders of the Celestial Seasonings Herb Tea Company, started Green Technologies in 1990 to apply that finding to home appliances. In the United States alone, there are more than 140 million refrigerators in use, accounting for an average of 16 percent of the household electric bill. That share can run as high as 25 percent in a small apartment.
Two years of research resulted in the GreenPlug. Connecting between wall socket and refrigerator, the device contains an analog computer that gives a motor full power (120 V on average) for start-up, then reduces the power to 106 V.
That boosts the efficiency, but a lot of factors affect how much electricity and money are saved. Line voltage varies from home to home.
Older refrigerators are the most overpowered and, thus, save the most energy with a GreenPlug. Refrigerators less than two years old are so efficient already that a GreenPlug actually makes them waste electricity.
The higher the voltage, the larger the difference a GreenPlug makes.
Higher power costs shorten the payback time. The population-weighted national average is 10 cents per kilowatt-hour. But some residents in Washington State pay 1.5 cents. Some in Alaska pay 416 cents.
Then come highly individual household factors like the number of children of refrigerator-opening age. All in all, the GreenPlug should save the average consumer $20 a year, says Steve Ehli, director of public relations for Green Technologies.
Controversy over the GreenPlug began when Bernard Deitrick, a project leader at Consumers Union, tested the device on refrigerators made in 1969, 1975, 1978 and 1992. His results appeared in an unfavorable review in the November issue of Consume Reports, drawing a barrage of challenges from Green Technologies as well as Green-Plug vendors and customers.
Although the GreenPlug lowered the voyage as it was designed to do, Consume Reports questioned how quickly—if ever—electricity savings attributable to the plug would repay its cost. People would be better of buying a new, high-efficiency refrigerator, the magazine advised...
Consumer Reports also said that the GreenPlug didn't give a claimed 25 percent savings worth $50 a year. The savings on the oldest model was the best at 8.6 percent, worth $20 a year.
Green Technologies responded that by November it had discontinued a pamphlet that implied that the GreenPlug could deliver a 25-percent savings. And it had never used the $50 figure.
Green Technologies ordered tests of the GreenPlug on up to 2800 refrigerators through next year. Mr. Ehli says the company will not put that data in stores. Instead, potential buyers will call an 800 numbers to learn how their model of refrigerator performed.
Meanwhile, there is little evidence of consumer dissatisfaction. Sales topped 45000 units last month. The return rate is less than 0.2 percent, Ehli says.

单选题 The availability of "green" products on store shelves in the U.S. is due mostly to a/an ______.
A. increased concern about the environment
B. decrease in the average family's income
C. increasing cost of electrical power
D. demand for money-saving technology

单选题 By calling Green Technologies a "fledgling" manufacturer (paragraph 2), the writer ______.
A. suggests it is incompetent
B. stresses its inexperience
C. commends its expertise
D. signifies its importance

单选题 According to the passage, the GreenPlug ______.
A. can only be used with older appliances
B. increases the efficiency of all appliances
C. cannot guarantee lower electric bills
D. only works if the power supply is constant

单选题 The electrical saving provided by the GreenPlug is influenced by a number of factors including ______.
A. the age of the plug
B. the number of outlets in the house
C. one's place of residence
D. the number of adults in the home

单选题 In the GreenPlug controversy, the position taken by Consumer Reports assumes that ______.
A. protecting the environment is all important
B. manufacturers never tell the truth
C. buyers purchase plugs to conserve energy
D. buyers purchase plugs to save money