GRE考试逻辑真题练习及答案

　　1．Drug companies lose money when manufacturing drugs that cure those suffering from rare diseases because selling a drug to only a few people usually does not recoup manufacturing expenses．Therefore，a company manufacturing any of the drugs that cure those suffering from loxemia，an extremely rare disease，will undoubtedly lose money．

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

　　（A）Several drugs that cure those suffering from loxemia also cure those suffering from very common illnesses．

　　（B）Most of those who contract loxemia also con-tract another illness concurrently．

　　（C）Most of the drug companies that manufacture drugs that cure rare diseases do not manufac-ture drugs that cure loxemia．

　　（D）A sizable number of people are afflicted with one or another rare disease even though each rare disease afflicts only a small number of people．

　　（E）The larger the amount of a drug that is manu-factured，the lower the manufacturing expense for each unit of the drug that is produced．

　　2．The tomb of a warrior killed in 1501 bears a sculpted portrait depicting him dressed for battle．Some his-torians attribute the portrait to an artist from that century，but of the many references to the tomb in surviving documents，none that predates the 1800's mentions the portrait．The portrait is therefore more likely the work of a much later artist．

　　Which of the following，if true，would also support the conclusion of the argument if substituted for the evidence given concerning the portrait？

　　（A）The portrait of the warrior was commissioned by the family of the warrior's widow．

　　（B）References in surviving documents mention that an artist was paid in 1525 for an unspecified number of works for the church in which the tomb is located

　　（C）The warrior is depicted in the portrait as wearing boots made of a material not used for boots until the 1700's．

　　（D）Some other art treasures from the church in which the tomb is located have been reliable dated to the 1400's．

　　（E）The portrait of the warrior on the tomb strongly resembles a portrait of him known to have been completed during his lifetime．

　　3．Scientist：More than 1，000 large asteroids regularly cross the Earth's path．Even though the probabil-ity of one colliding with the Earth is extremely slight，we should do whatever we can to reduce that probability since any such collision would be catastrophic．The best way to avoid such a disaster is to deflect the asteroids．The only known way of deflecting asteroids is by hitting them with nuclear weapons that would be stored in space stations．

　　The scientist's claims are structured so as to lead to which of the following conclusions？

　　（A）Nuclear technology is the only technology that can plausibly be used to prevent natural catastrophes．

　　（B）Nuclear weapons should be deployed in space．

　　（C）No catastrophe has yet been caused by the collision of an asteroid with the Earth．

　　（D）The 1，000 large asteroids that cross the Earth's path pose only an extremely slight risk of colliding with the Earth．

　　（E）There is currently no acceptable use to which nuclear weapons can be put，aside from pro-tecting the Earth from asteroids．

　　4．It has long been thought that high levels of the hor-mone testosterone contribute to the onset of heart disease in men．However，this view cannot be correct，since men who have heart disease typically show significantly lower levels of testosterone than do men who have not had heart disease．

　　The argument above assumes which of the following？

　　（A）Many men who have never had heart disease have unusually low levels of testosterone．

　　（B）Having heart disease does not significantly lower the level of testosterone in men．

　　（C）Levels of hormones other than testosterone significantly affect the likelihood that a man will develop heart disease．

　　（D）Heart disease and lowered testosterone levels in men are the effects of a single common cause．

　　（E）High levels of testosterone have never been thought to contribute to a serious disease other than heart disease．

　　5．People who engage in scuba diving are healthier，on average，than people who do not engage in this activity．Therefore，scuba diving tends to promote improved health．

　　The argument is most vulnerable to criticism on the grounds that it

　　（A）presupposes that everyone who takes up scuba diving does so solely for health reasons

　　（B）leads to a further and falsifiable conclusion that no one can achieve good health without engaging in scuba diving

　　（C）fails to point out that a small number of people are seriously injured in scuba diving accidents each year

　　（D）treats a precondition for improving one's health as though it were something that by itself could ensure good health

　　（E）overlooks the possibility that people generally do not take up scuba diving unless they are in good health

　　6．Which of the following most logically completes the argument below？In recent years，the proportion of car buyers who buy new cars rather than used cars has declined．Some consumers have attributed this change to an increase in new-car prices．As evidence of the price increase，they cite figures that show that，even adjusting for inflation，the price that the buyer of a new car pays，on average，is far higher now than a few years ago．

　　This evidence is unpersuasive，however，because

　　（A）the value of a car that is bought new declines much more rapidly than does the value of a car that is bought used

　　（B）after someone has bought a car，it might be several years before that person next buys a car

　　（C）a decline in the proportion of car buyers who buy new cars must necessarily mean that the proportion who buy used cars has increased

　　（D）the relative increase in used-car sales might be explained by the decisions of only a small proportion of all car buyers

　　（E）the change in the average price paid for a new car could result solely from more people's rejecting inexpensive new cars in favor of used cars

　　7．In Bassaria a group of that country's most senior judges has criticized the uniform mandatory sentences recently introduced for certain specific crimes．The judges argue that such sentences，by depriving them of all discretion in setting sentences，make it impos-sible for them to consider either aggravating or exten-uating circumstances and so make it impossible to achieve true justice─the fitting of the severity of the punishment to the gravity of the particular crime．

　　Which of the following，if true，provides the strongest evidence for the claim that in Bassaria the newly introduced mandatory sentences are not necessarily a change for the worse with respect to achieving true justice as defined in the argument？

　　（A）Before mandatory sentencing，judges in eastern Bassaria imposed strikingly different sentences from those in western Bassaria for equally grave instances of the same kind of offense．

　　（B）In Bassaria the frequency of crimes that have been made subject to mandatory sentences is lower now than it was just prior to the intro-duction of mandatory sentencing．

　　（C）The law introducing mandatory sentences was passed in the legislature of Bassaria by a large majority and is unlikely to be repealed in the foreseeable future．

　　（D）There used to be a wide difference between the minimum and the maximum sentences allowed by law in cases of crimes now subject to man-datory sentences．

　　（E）In Bassaria judges are appointed for life and are thus not easily influenced by political pressure groups．