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3. Modern navigation systems, which are found in most
of today’s commercial aircraft, are made with
low-power circuitry, which is more susceptible to
interference than the vacuum-tube circuitry found in
older planes. During landing, navigation systems
receive radio signals from the airport to guide the
plane to the runway. Recently, one plane with
low-power circuitry veered off course during landing,
its dials dimming, when a passenger turned on a
laptop computer. Clearly, modern aircraft navigation
systems are being put at risk by the electronic
devices that passengers carry on board, such as
cassette players and laptop computers.
The logic chain of the argument is that because when a passenger turned on a laptop computer, on plane with low-power circuitry veered off course during landing its dials dimming, we can conclude that modern aircraft navigation systems are being put at risk by the electronic devices that passengers carry on board, such as cassette players and laptop computers. In short, two things happened simultaneously, one caused the other. In order to weaken the argument, we need to break the causality. Perhaps, the relationship is reversed, or even no related to each other.
Which one of the following, if true, LEAST
strengthens the argument above?
(A) After the laptop computer was turned off, the
plane regained course and its navigation
instruments and dials returned to normal.
This answer choice actually strengthens the causality.
When the cause is absent, the effect does not occur.
(B) When in use all electronic devices emit
electromagnetic radiation, which is known to
interfere with circuitry.
This answer choice reveals that using electronic devices can interfere with circuitry.
This answer strengthens the argument by showing that the data used to demonstrate the causality is accurate.
(C) No problems with navigational equipment or
instrument dials have been reported on
flights with no passenger-owned electronic
devices on board.
From the opposite, we can see that this answer choice strengthens the argument in some degree.
This answer strengthens the argument by showing that when the cause is absent, the effect does no occur.
(D) Significant electromagnetic radiation from
portable electronic devices can travel up to
eight meters, and some passenger seats on
modern aircraft are located within four meters
of the navigation systems.
It still points out the radiation can inference with the navigation systems.
This answer strengthens the argument by showing that the data used to make the conclusion is accurate.
(E) Planes were first equipped with low-power
circuitry at about the same time portable
electronic devices became popular.
In this case, it does not have effect on the causality, since the time cannot prove the causal relationship between them. BA
13.(25752-!-item-!-188;#058&002668)
An unusually severe winter occurred in Europe after the continent was blanketed by a blue haze resulting from the eruption of the Laki Volcano in the European republic of Iceland in the summer of 1984. Thus, it is evident that major eruptions cause the atmosphere to become cooler than it would be otherwise.
Which of the following statements, if true, most seriously weakens the argument above?
A) The cooling effect triggered by volcanic eruptions in 1985 was counteracted by an unusual warming of Pacific waters.
Since the Pacific waters were unusual warming, the example is unrepresentative.
It still reveals that eruptions can cause the atmosphere to become cooler than it would be.
(B) There is a strong statistical link between volcanic eruptions and the severity of the rainy season in India.
Actually, this answer choice strengthens the argument.
(C) A few months after El Chichn's large eruption in April 1982, air temperatures throughout the region remained higher than expected, given the long-term weather trends.
The same to A.
In this case, it points out that the large eruption can cause the air temperatures throughout the region higher than expected. Please read carefully.
(D) The climatic effects of major volcanic eruptions can temporarily mask the general warming trend resulting from an excess of carbon dioxide in the atmosphere.
In this case, it cast doubt on the argument, since the general warming trend resulting from an excess o f carbon dioxide in the atmosphere can be caused by major volcanic eruptions. BA
I missed the meaning of “mask” and did not read carefully about what “resulting from”.
In fact, this answer choice strengthens the argument, rather than weakens.
(E) Three months after an early springtime eruption in South America during the late 19th century, sea surface temperatures near the coast began to fall.
Actually, this answer choice strengthens the argument.
14.(25938-!-item-!-188;#058&002908)
Most household appliances use electricity only when in use. Many microwave ovens, however, have built-in clocks and so use some electricity even when they are not in use. The clocks each consume about 45 kilowatt-hours per year. Therefore, households whose microwave oven has no built-in clock use 45 kilowatt-hours per year less, on average, than do comparable households whose microwave oven is otherwise similar but has a built-in clock.
Which of the following is an assumption on which the argument depends?
(A) Households that do not have a microwave oven use less energy per year, on average, than do households that have a microwave oven.
Shell Game: The comparison between households that do not have a microwave oven and households that have a microwave oven is irrelevant.
(B) Microwave ovens with a built-in clock do not generally cost more to buy than microwave ovens without a built-in clock.
The prices of them are outside the scope of the argument.
(C) All households that have a microwave oven also have either a gas oven or a conventional electric oven.
Who knows? It is irrelevant.
(D) Households whose microwave oven does not have a built-in clock are no more likely to have a separate electric clock plugged in than households whose microwave oven has one.
Yes, in this case, this answer choice rules out the hole in the argument, thus strengthening the logic chain. BA
(E) There are more households that have a microwave oven with a built-in clock than there are households that have a microwave oven without a built-in clock.
This is outside the scope of the argument.
15.(25986-!-item-!-188;#058&002914)
Some airlines allegedly reduce fares on certain routes to a level at which they lose money, in order to drive competitors off those routes. However, this method of eliminating competition cannot be profitable in the long run. Once an airline successfully implements this method, any attempt to recoup the earlier losses by charging high fares on that route for an extended period would only provide competitors with a better opportunity to undercut the airline's fares.
Which of the following, if true, most seriously weakens the argument?
(A) In some countries it is not illegal for a company to drive away competitors by selling a product below cost.
How about the other countries?
(B) Airline executives generally believe that a company that once underpriced its fares to drive away competitors is very likely to do so again if new competitors emerge.
It seems to be a contender. I choose it! BA
it states that other airlines are likely to continue to stay away, even after the big mean price-cutting airline raises its prices back up. (if their executives believe that 'big air' will simply lower its prices again if they try to wedge back into the market, then they'll stay out.) from Manhattan
(C) As part of promotions designed to attract new customers, airlines sometimes reduce their ticket prices to below an economically sustainable level.
The promotions designed to attract new customers are outside the scope of the argument, which talks about the aim to drive competitors off.
(D) On deciding to stop serving particular routes, most airlines shift resources to other routes rather than reduce the size of their operations.
Deciding to stop serving particular routes is outside the scope of the argument.
(E) When airlines dramatically reduce their fares on a particular route, the total number of air passengers on that route increases greatly.
If competitors use this strategy, they can benefit from it, thus making the argument much less valid.
16.(26678-!-item-!-188;#058&003277)
When an airplane is taken out of service for maintenance, it is often repainted as well, and during the repainting no other maintenance work can be done on the plane. In order to reduce maintenance time, airline officials are considering using a new nontoxic plastic film instead of paint. The film takes just as long to apply as paint does, but many other maintenance tasks can be carried out at the same time.
Which of the following, if true, is further evidence that using the film will help the airline officials achieve their goal?
(A) Unlike paint, the film gives a milky tone to certain colors.
The colors are irrelevant.
(B) At the end of its useful life, the film can be removed much more quickly than paint can.
At first glance, the answer choice seems to be irrelevant, but if the film can be removed much more quickly than paint can, the time to maintenance can be reduced. BA
(C) The film can be applied only by technicians who have received special training.
In some degree, this answer choice weakens the argument, since the workers needs some special training, which may increase the whole time for maintenance.
(D) The metal exteriors of airplanes have to be protected from high temperatures and caustic chemicals such as exhaust gases.
In this case, other work may not be conducted, considering the influence to the metal exteriors of airplanes.
(E) Even at speeds considerably higher than the normal speed of a passenger jet, the film remains securely attached.
This is out of the scope of the argument.
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发表于 2012-7-10 21:51:42
ne plane with L veered off course during landing because a passenger turn on a laptop.
