11.Installing scrubbers in smokestacks and switching to cleaner-burning fuel are the two methods available to Northern Power for reducing harmful emissions from its plants. Scrubbers will reduce harmful emissions more than cleaner-burning fuels will. Therefore，by installing scrubbers， Northern Power will be doing the most that can be done to reduce harmful emissions from its plants.

　　Which of the following is an assumption on which the argument depends？

　　（A） Switching to cleaner-burning fuel will not be more expensive than installing scrubbers.

　　（B） Northern Power can choose from among various kinds of scrubbers，some of which are more effective than others.

　　（C） Northern Power is not necessarily committed to reducing harmful emissions from its plants.

　　（D） Harmful emissions from Northern Power's plants cannot be reduced more by using both methods together than by the installation of scrubbers alone.

　　（E） Aside from harmful emissions from the smoke-stacks of its plants， the activities of Northern Power do not cause significant air pollution.

　　12.In 1990 all of the people who applied for a job at Evco also applied for a job at Radeco，and Evco and Radeco each offered jobs to half of these applicants cants. Therefore，every one of these applicants must have been offered a job in 1990.

　　The argument above is based on which of the following assumptions about these job applicants？

　　（A）All of the applicants were very well qualified for a job at either Evco or Radeco.

　　（B） All of the applicants accepted a job at either Evco or Radeco.

　　（C） None of the applicants was offered a job by both Evco and Radeco.

　　（D） None of the applicants had applied for jobs at places other than Evco and Radeco.

　　（E） None of the applicants had perviously worked for either Evco or Radeco.

　　13.Y has been believed to cause Z. A new report， noting that Y and Z are often observed to be preceded by X， suggests that X， not Y， may be the cause of Z.Which of the following further observations would best support the new report's suggestion？

　　（A） In cases where X occurs but Y does not， X is usually followed by Z.

　　（B） In cases where X occurs， followed by Y， Y is usually followed by Z.

　　（C） In cases where Y occurs but X does not， Y is usually followed by Z.

　　（D） In cases where Y occurs but Z does not， Y is usually preceded by X.

　　（E） In cases where Z occurs， it is usually preceded by X and Y.

　　14.A cost-effective solution to the problem of airport congestion is to provide high-speed ground transportation between major cities lying 200 to 500 miles apart. The successful implementation of this plan would cost far less than expanding existing airports and would also reduce the number of airplanes clogging both airports and airways.

　　Which of the following， if true， could proponents of the plan above most appropriately cite as a piece of evidence for the soundness of their plan？

　　（A）An effective high-speed ground-transportation system would require major repairs to many highways and mass-transit improvements.

　　（B）One-half of all departing flights in the nation's busiest airport head for a destination in a major city 225 miles away. （C）The majority of travelers departing from rural airports are flying to destinations in cities over 600 miles away.

　　（D） Many new airports are being built in areas that are presently served by high-speed ground-transportation systems.

　　（E） A large proportion of air travelers are vacationers who are taking long-distance flights.

　　15.Which of the following， if true， would most strengthen the conclusion drawn in the second sentence？

　　（A） Commercial airliners are already required by law to be equipped with extremely sophisticated radar systems.

　　（B） Centrally located airports are experiencing over-crowded airspace primarily because of sharp increases in commercial-airline traffic.

　　（C） Many pilots of private planes would rather buy radar equipment than be excluded from centrally located airports.

　　（D） The number of midair collisions that occur near centrally located airports has decreased in recent years.

　　（E） Private planes not equipped with radar systems cause a disproportionately large number of midair collisions around centrally located airports.

　　16.In Argonia the average rate drivers pay for car accident insurance is regulated to allow insurance companies to make a reasonable profit. Under the regulations， the rate any individual driver pays never depends on the actual distance driven by that driver each year. Therefore， Argonians who drive less than average partially subsidize the insurance of those who drive more than average.

　　The conclusion above would be properly drawn if it were also true that in Argonia

　　（A） the average accident insurance rate for all drivers rises whenever a substantial number of new drivers buy insurance

　　（B） the average cost to insurance companies of insuring drivers who drive less than the annual average is less than the average cost of insuring drivers who drive more than the annual average

　　（C） the lower the age of a driver， the higher the insurance rate paid by that driver

　　（D） Insurance company profits would rise substantially if drivers were classified in terms of the actual number of miles they drive each year

　　（E） Drivers who have caused insurance companies to pay costly claims generally pay insurance rates that are equal to or lower than those paid by other drivers

　　17.Despite the approach of winter， oil prices to industrial customers are exceptionally low this year and likely to remain so. Therefore， unless the winter is especially severe， the price of natural gas to industrial customers is also likely to remain low.

　　Which of the following， if true， provides the most support for the conclusion above？

　　（A） Long-term weather forecasts predict a mild winter.

　　（B） The industrial users who consume most natural gas can quickly and cheaply switch to using oil instead.

　　（C） The largest sources of supply for both oil and natural gas are in subtropical regions unlikely to be affected by winter weather.

　　（D） The fuel requirements of industrial users of natural gas are not seriously affected by the weather.

　　（E） Oil distribution is more likely to be affected by severe winter weather than is the distribution of natural gas.

　　18.Most geologists believe oil results from chemical transformations of hydrocarbons derived from organisms buried under ancient seas. Suppose，instead， that oil actually results from bacterial action on other complex hydrocarbons that are trapped within the Earth. As is well known， the volume of these hydrocarbons exceeds that of buried organisms. Therefore， our oil reserves would be greater than most geologists believe.

　　Which of the following， if true， gives the strongest support to the argument above about our oil reserves？

　　（A） Most geologists think optimistically about the Earth's reserves of oil.

　　（B） Most geologists have performed accurate chemical analyses on previously discovered oil reserves.

　　（C） Ancient seas are buried within the Earth at many places where fossils are abundant.

　　（D） The only bacteria yet found in oil reserves could have leaked down drill holes from surface contaminants.

　　（E） Chemical transformations reduce the volume of buried hydrocarbons derived from organisms by roughly the same proportion as bacterial action reduces the volume of other complex hydrocarbons.

　　keys： ACBDB AAADE DCABE BBE