【每日逻辑练习第二季【2-3】

zxppx

看来今天的精炼很难啊！
4.

Amphibian populations are declining in numbers
worldwide. Not coincidentally, the earth’s ozone
layer has been continuously depleted throughout the
last 50 years. Atmospheric ozone blocks UV-B, a
type of ultraviolet radiation that is continuously
produced by the sun, and which can damage genes.
Because amphibians lack hair, hide, or feathers to
shield them, they are particularly vulnerable to UV-B
radiation. In addition, their gelatinous eggs lack the
protection of leathery or hard shells. Thus, the
primary cause of the declining amphibian population
is the depletion of the ozone layer.

The logic chain of the argument is that because of decline in the population of amphibians and in the amount of ozone, the latter caused the former. What’s more, UV-B can harm amphibians with the depletion of the ozone layer. In order to solve the argument, we need to find the right answer, which cannot strengthen the causality provided in the argument.
Each of the following, if true, would strengthen the
argument EXCEPT:

(A) Of the various types of radiation blocked by
atmospheric ozone, UV-B is the only type
that can damage genes.

At first glance, it seems to be irrelevant. But a more thorough analysis reveals that it is useful for the argument. If other factors can reduce the population of amphibians, the reasoning referred in the argument will be weakened. 但问题是即使有其他的射线可以造成伤害，请注意选项中的限定词“被臭氧层所阻挡的”，如果臭氧层不被破坏，即使有其他的射线，也不能造成伤害，所以这个选项并没有加强结论！

But please notice the conclusion, which refers to the amphibian population and the ozone layer, has nothing to do with the UV-B, even though UV-B can harm amphibians provided by the argument. So whether UV-B is the only type of the various types of radiation blocked by atmospheric ozone can damage genes has no effect on the argument.
(B) Amphibian populations are declining far more
rapidly than are the populations of
nonamphibian species whose tissues and
eggs have more natural protection from
UV-B.

Actually, this answer choice strengthens the argument.

This choice strengthens the argument by showing that when the cause in the nonamphibian speices is absent, the effect does not occur.
(C) Atmospheric ozone has been significantly
depleted above all the areas of the world in
which amphibian populations are declining.

The same to B.

This strengthens the argument by showing that when the cause occurs, the effect occurs, too.
(D) The natural habitat of amphibians has not
become smaller over the past century.

In this case, we can find out that if the natural habitat of amphibians has not become smaller over the past century, and that if the earth’s ozone layer has been continuously depleted throughout the past half century, these two seems to irrelevant. BA

事实上，如果栖息地减少也会造成该物种的数量减少，排除他因，加强结论

This answer strengthens the argument by eliminating an alternative cause for the effect. Had the natural habitat of amphibians become smaller over the years (from say, human encroachment or climatic change) then that shrinkage would have offered an alternative explanation for the decline in the population of amphibians.
(E) Amphibian populations have declined
continuously for the last 50 years.

The same to B.

This answer choice strengthens the argument by showing that the decline in amphibians has mirrored the depletion of ozone layer, thus affirming the data used to make the conclusion.

17.
At present the Hollywood Restaurant has only standard-height tables. However, many customers come to watch the celebrities who frequent the Hollywood, and they would prefer tall tables with stools because such seating would afford a better view of the celebrities. Moreover, diners seated on stools typically do not stay as long as diners seated at standard-height tables. Therefore, if the Hollywood replaced some of its seating with high tables and stools, its profits would increase.
The argument is vulnerable to criticism on the grounds that it gives reason to believe that it is likely that

(A) some celebrities come to the Hollywood to be seen, and so might choose to sit at the tall tables if they were available

This answer choice strengthens the argument by showing that tall tables are more popular than standard-height.
(B) the price of meals ordered by celebrities dining at the Hollywood compensates for the longer time, if any, they spend lingering over their meals

The argument has pointed out that many customers prefer tall tables with stools. If they can linger longer time, the price of meals can compensates for the time.
(C) a customer of the Hollywood who would choose to sit at a tall table would be an exception to the generalization about lingering

“Exception to the generalization about lingering” means these customers would stay very long time, thus reducing the total customers in the restaurant and weakening the argument. BA

the 'generalization about lingering' is the idea that people won't sit at tall tables for as long as at short tables. Yet, according to the passage, the customers at tall tables will probably be there to gawk at celebrities, so they will probably stay for a long time - the 'exception' mentioned in this answer choice.From Manhattan
(D) a restaurant's customers who spend less time at their meals typically order less expensive meals than those who remain at their meals longer

This answer choice supports the high tables and stools.
(E) with enough tall tables to accommodate all the Hollywood's customers interested in such seating, there would be no view except of other tall tables

I do not understand the latter part in the sentence. In fact, it does not refer to the lingering time of customers, thus not weakening the argument.



18.
The Calex Telecommunications Company is planning to introduce cellular telephone service into isolated coastal areas of Caladia, a move which will require considerable investment. However, the only significant economic activity in these areas is small-scale coffee farming, and none of the coffee farmers make enough money to afford the monthly service fees that Calex would have to charge to make a profit. Nevertheless, Calex contends that making the service available to these farmers will be profitable.
Which of the following, if true, provides the strongest support for Calex's contention?

(A) Currently, Caladian coffee farmers are forced to sell their coffee to local buyers at whatever price those buyers choose to pay because the farmers are unable to remain in contact with outside buyers who generally offer higher prices.

In this case, the answer choice strengthens Calex’ contention by showing that if it can help those farmers to contact with outside buyers who generally offer higher prices, the revenues of the farmers will increase, and they can pay the fees. BA
(B) In the coastal areas of Caladia where Calex proposes to introduce cellular telephone service, there is currently no fixed-line telephone service because fixed-line companies do not believe that they could recoup their investment.

Actually, this answer choice weakens the argument.
(C) A cellular telephone company can break even with a considerably smaller number of subscribers than a fixed-line company can, even in areas such as the Caladian coast, where there is no difficult terrain to drive up the costs of installing fixed lines.

The comparison between a cellular telephone and a fixed-line company is irrelevant.
(D) Calex bases its monthly fees for cellular telephone service in a given region partly on the cost of installing the necessary equipment to provide the service there.

Since we have already known that the cost of installing is considerable, and these farmers cannot afford the monthly fees, this answer choice cannot strengthen the argument.
(E) Calex has for years made a profit on cellular telephone service in Caladia's capital city, which is not far from the coastal region.

Since the conditions between the two places are different, we cannot make sure Calex will make a profit on cellular telephone service in the coastal region.



19.
With a record number of new companies starting up in Derderia and with previously established companies adding many jobs, a record number of new jobs were created last year in the Derderian economy. This year, previously established companies will not be adding as many new jobs overall as such companies added last year. Therefore, unless a record number of companies start up this year, Derderia will not break its record for new jobs created.
Which of the following is an assumption on which the argument relies?

(A) Each year, new companies starting up create more new jobs overall than do previously established companies.

The argument does not need this assumption.
(B) Companies established last year will not add a greater number of jobs overall this year than they did last year.

It has been referred in the argument.
(C) This year, the new companies starting up will not provide substantially more jobs per company than did new companies last year.

In this case, it is necessary for the logic chain of the argument, since if, this year, the new companies starting up add more new jobs per company than did new companies last year, the overall jobs created this year may still surpass those of last year. BA
(D) This year, the overall number of jobs created by previously established companies will be less than the overall number of jobs lost at those companies.

Jobs lost are outside the scope of the argument.
(E) The number of jobs created in the Derderian economy last year was substantially larger than the number of jobs lost last year.

The same to D.



20.
During the past year, Pro-Tect Insurance Company's total payout on car-theft claims has been larger than the company can afford to sustain. Pro-Tect cannot reduce the number of car-theft policies it carries, so it cannot protect itself against continued large payouts that way. Therefore, Pro-Tect has decided to offer a discount to holders of car-theft policies whose cars have antitheft devices. Many policyholders will respond to the discount by installing such devices, since the amount of the discount will within two years typically more than cover the cost of installation. Thus, because cars with antitheft devices are rarely stolen, Pro-Tect's plan is likely to reduce its annual payouts.
In the argument above, the two portions in boldface play which of the following roles?

(A) The first and the second are both evidence offered by the argument as support for its main conclusion.

The second is the main conclusion.
(B) The first presents a problem a response to which the argument assesses; the second is the judgment reached by that assessment.

The second is the main conclusion, and it is a judgment reached by the adoption of antitheft devices, while the first presents a problem for the reason of the adoption of antitheft devices. BA
(C) The first is the position the argument seeks to establish; the second is a judgment the argument uses to support that position.

The first is not the position the argument seeks to establish, neither does the second support the first.
(D) The first is a development that the argument seeks to explain; the second is a prediction the argument makes in support of the explanation it offers.

The second is not in support of the explanation, because the logic chain is reversed.
(E) The first presents a development whose likely outcome is at issue in the argument; the second is a judgment the argument uses in support of its conclusion about that outcome.

The second is not used to support the conclusion about the outcome.