1. (Z) Highway Official: When resurfacing our concrete bridges, we should use electrically conductive concrete (ECC) rather than standard concrete. In the winter, ECC can be heated by passing an electric current through it, thereby preventing ice buildup. The cost of the electricity needed is substantially lower than the cost of the de-icing salt we currently use.
Taxpayer: But construction costs for ECC are much higher than for standard concrete, so your proposal is probably not justifiable on economic grounds.
Which of the following, if true, could best be used to support the highway official’s proposal in the face of the taxpayer’s objection?
A. The use of de-icing salt causes corrosion of the reinforcing steel in concrete bridge decks and damage to the concrete itself, thereby considerably shortening the useful life of concrete bridges.
B. Severe icing conditions can cause power outages and slow down the work of emergency crews trying to get power restored.
C. In weather conditions conducive to icing, ice generally forms on the concrete surfaces of bridges well before it forms on parts of the roadway that go over solid ground.
D. Aside from its potential use for de-icing bridges, ECC might also be an effective means of keeping other concrete structures such as parking garages and airport runways ice free.
E. If ECC were to be used for a bridge surface, the electric current would be turned on only at times at which ice was likely to form.
2.(Z) Consumers planning to buy recreational equipment tend to buy higher quality,more expensive equipment when the economy is strong than when it is
weak. Hill and Dale is a business that sells high-quality, expensive camping
and hiking equipment in Boravia. Although all the signs are that Boravia’s
economy is now entering a period of sustained strength, the managers
of the business do not expect a substantial increase in sales.
Which of the following, if true, would provide the strongest justification for the managers’ judgment?
A. A significant proportion of Hill and Dale’s sales are made tocustomers who enter the store in order to buy one particularitem but, once there, find other items to buy as well.
B. In Boravia when the economy is strong, those who mightotherwise go camping tend to take vacations overseas.
C. The economic upturn is likely to allow Boravia’s nati-onal parks, where most of the camping and hiking is done, to receive extra funding to improve their visitor facilities.
D. Advances in materials technology have led to thedevelopment of hiking and camping equipment thatis more comfortable and lightweight than before.
E. Many people in Boravia not only are committed to preserving the country’s wilderness areas but also are interested in spending some time in them.
3.(Z有争议)People who have spent a lot of time in contact with animals often develop
animal-induced allergies, some of them quite serious. In a survey of current
employees in major zoos, about 30 percent had animal-induced allergies.
Based on this sample, experts conclude that among members of the general
population who have spent a similarly large amount of time in close contact
with animals, the percentage with animal-induced allergies is not 30 percent
but substantially more.
Which of the following, if true, provides the strongest grounds for the experts’
conclusion?
A. A zoo employee who develops a serious animal-induced allergy is very
likely to switch to some other occupation.
B. A zoo employee is more likely than a person in the general population
to keep one or more animal pets at home
C. The percentage of the general population whose level of exposure to
animals matches that of a zoo employee is quite small.
D. Exposure to domestic pets is, on the whole, less likely to cause animal-
induced allergy than exposure to many of the animals kept in zoos.
E. Zoo employees seldom wear protective gear when they handle animals
in their care.
4.(Z)In polluted environments, dolphins gradually accumulated toxins in their body fat, and the larger the dolphin the more accumulated toxin it can tolerate. Nearly 80 percent of the toxins a female dolphin has accumulated pass into the fat-rich milk her nursing calf ingests. Therefore, the unusually high mortality rate among dolphin calves in the industrially contaminated waters along Florida’s Gulf Coast is probably the result of their being poisoned by their mother’s milk.
Which of the following, if true, most strengthens the argument?
A. The survival rate of firstborn dolphin calves in the area along Florida’s Gulf Coast is highest for those whose mothers were killed before they were weaned.
B. The rate at which adult dolphins living in the waters along Florida’s Gulf Coast accumulate toxins is no higher than that of adult dolphins in comparably polluted waters elsewhere.
C. Among dolphin calves born in the area along Florida’s Gulf Coast, the mortality rate is highest among those with living siblings.
D. As dolphins age, they accumulate toxins from the environment more slowly than when they were young.
E. Dolphins, like other marine mammals, have a higher proportion of body fat than do most land mammals.
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