GMAT考生想要在GMAT逻辑部分取得高分，需要提高自己的逻辑思维能力，那么逻辑思维能力可以通过哪些方式获得提升呢，比较实用的方法就是不断加强自己逻辑方面的练习。我们一起来看一下GMAT逻辑经典练习题TEST第二十五部分。

1.Since a rhinoceros that has no horn is worthless to poachers, the Wildlife Protection Committee plans to protect selected rhinoceroses from being killed by poachers by cutting off the rhinos’ horns.

The Wildlife Protection Committee’s plan assumes that

(A) poachers do not kill rhinos that are worthless to them

(B) hornless rhinos pose less of a threat to humans, including poachers, than do rhinos that have horns

(C) rhinos are the only animals poachers kill for their horns

(D) hornless rhinos can successfully defend their young against nonhuman predators

(E) imposing more stringent penalties on poachers will not decrease the number of rhinos killed by poachers

2.Crimes are mainly committed by the young, and for this reason merely increasing the number of police officers or expenditures on police services has little effect on reducing the crime rate. In fact, the only factor associated with a crime-rate drop is a decrease in the number of people in the community aged fourteen to thirty.

The findings above can best serve as part of an argument against

(A) the likelihood that any law enforcement program will be effective in reducing the crime rate within a short time

(B) increasing prison terms for young people found guilty of crimes

(C) introducing compulsory military conscription for people aged seventeen to nineteen

(D) raising the age at which students are permitted to leave school

(E) a community’s plan to increase the number of recreational and educational activities in which young adults can participate

3.A 20 percent decline in lobster catches in Maine waters since 1980 can be justifiably blamed on legislation passed in 1972 to protect harbor seals. Maine’s population of harbor seals is now double the level existing before protection was initiated, and these seals are known to eat both fish and lobsters.

Which of the following, if true, would most seriously weaken the argument above?

(A) Harbor seals usually eat more fish than lobsters, but the seals are natural predators of both.

(B) Although harbor seals are skillful predators of lobsters, they rarely finish eating their catch.

(C) Harbor seals attract tourists to Maine’s coastal areas, thus revitalizing the local economy.

(D) Authors of the 1972 legislation protecting harbor seals were convinced that an increase in that animal’s numbers would not have a measurably negative impact on the lobster catch.

(E) The record lobster harvests of the late 1970’s removed large numbers of mature lobsters from the reproductive stock.

4.Politician: Fewer people are entering the labor market now than previously. If the economy grows, the demand for motivated and educated people will far outstrip the supply. Some companies have already started to respond to this labor-market situation by finding better ways to keep their current employees. Their concern is a sure indicator that the economy is growing.

Which of the following is the best criticism of the politician’s reasoning?

(A) The fact that companies are making prudent preparations for a possible future development does not mean that this development is already taking place.

(B) The fact that some companies now try harder to keep their employees does not mean that they used to be indifferent to employee morale.

(C) The fact that demand will outstrip supply does not mean that there will be no supply at all.

(D) The fact that the number of new entrants into the labor market is declining does not mean that the number of new entrants is lower than it has ever been.

(E) The fact that current employees have become more valuable to some companies does not mean that those employees will do their jobs better than they used to.

5.Under current federal law, employers are allowed to offer their employees free parking spaces as a tax-free benefit, but they can offer employees only up to $180 per year as a tax-free benefit for using mass transit. The government could significantly increase mass transit ridership by raising the limit of this benefit to meet commuters’ transportation costs. The proposal above to increase mass transit ridership assumes that (A) current mass transit systems are subject to unexpected route closings and delays (B) using mass transit creates less air pollution per person than using a private automobile (C) the parking spaces offered by employers as tax-free benefits can be worth as much as$2,500 per year

(D) many employees are deterred by financial considerations from using mass transit to commute to their places of employment

(E) because of traffic congestion on major commuter routes, it is often faster to travel to one’s place of employment by means of mass transit than by private automobile

6.Which of the following best completes the passage below?

“Government” does not exist as an independent entity defining policy. Instead there exists a group of democratically elected pragmatists sensitive to the electorate, who establish policies that will result in their own reelection. Therefore, if public policy is hostile to, say, environmental concerns, it is not because of governmental perversity but because elected officials believe that______

(A) environmentalists would be extremely difficult to satisfy with any policy, however environmentally sound

(B) environmental concerns are being accommodated as well as public funds permit

(C) the public is overly anxious about environmental deterioration

(D) the majority of voters vote for certain politicians because of those politicians’ idiosyncratic positions on policy issues

(E) the majority of voters do not strongly wish for a different policy

7.Fresh potatoes generally cost about $2 for a 10-pound bag, whereas dehydrated instant potatoes cost, on average, about$3 per pound. It can be concluded that some consumers will pay 15 times as much for convenience, since sales of this convenience food continue to rise.

Which of the following, if true, indicates that there is a major flaw in the argument above?

(A) Fresh potatoes bought in convenient 2-pound bags are about $1 a bag, or 2 1/2 times more expensive than fresh potatoes bought in 10-pound bags. (B) Since fresh potatoes are 80 percent water, one pound of dehydrated potatoes is the equivalent of 5 pounds of fresh potatoes. (C) Peeled potatoes in cans are also more expensive than the less convenient fresh potatoes. (D) Retail prices of dehydrated potatoes have declined by 20 percent since 1960 to the current level of about$3 a pound.

(E) As a consequence of labor and processing costs, all convenience foods cost more than the basic foods from which they are derived.

8.Consumers in California seeking personal loans have fewer banks to turn to than do consumers elsewhere in the United States. This shortage of competition among banks explains why interest rates on personal loans in California are higher than in any other region of the United States.

Which of the following, if true, most substantially weakens the conclusion above?

(A) Because of the comparatively high wages they must pay to attract qualified workers, California banks charge depositors more than banks elsewhere do for many of the services they offer.

(B) Personal loans are riskier than other types of loans, such as home mortgage loans, that banks make.

(C) Since bank deposits in California are covered by the same type of insurance that guarantees bank deposits in other parts of the United States, they are no less secure than deposits elsewhere.

(D) The proportion of consumers who default on their personal loans is lower in California than in any other region of the United States.

(E) Interest rates paid by California banks to depositors are lower than those paid by banks in other parts of the United States because in California there is less competition to attract depositors.

9.Technically a given category of insurance policy is underpriced if, over time, claims against it plus expenses associated with it exceed total income from premiums. But premium income can be invested and will then yield returns of its own. Therefore, an underpriced policy does not represent a net loss in every case.

The argument above is based on which of the following assumptions?

(A) No insurance policies are deliberately underpriced in order to attract customers to the insurance company offering such policies.

(B) A policy that represents a net loss to the insurance company is not an underpriced policy in every case.

(C) There are policies for which the level of claims per year can be predicted with great accuracy before premiums are set.

(D) The income earned by investing premium income is the most important determinant of an insurance company’s profits.

(E) The claims against at least some underpriced policies do not require paying out all of the premium income from those policies as soon as it is earned.

10.Purebred cows native to Mongolia produce, on average, 400 liters of milk per year; if Mongolian cattle are crossbred with European breeds, the crossbred cows can produce, on average, 2,700 liters per year. An international agency plans to increase the profitability of Mongolia’s dairy sector by encouraging widespread crossbreeding of native Mongolian cattle with European breeds.

Which of the following, if true, casts the most serious doubt on the viability of the agency’s plan?

(A) Not all European breeds of cattle can be successfully bred with native Mongolian cattle.

(B) Many young Mongolians now regard cattle raising as a low-status occupation because it is less lucrative than other endeavors open to them.

(C) Mongolia’s terrain is suitable for grazing native herds but not for growing the fodder needed to keep crossbred animals healthy.

(D) Cowhide and leather products, not milk, make up the bulk of Mongolia’s animal product exports to Europe.

(E) Many European breeds of cattle attain average milk production levels exceeding 2,700 liters.