2012GMAT逻辑推理训练内容希望考生充分利用，总结做题技巧，充分备考。
A researcher discovered that people who have low levels of immune-system activity tend to score much lower on tests of mental health than do people with normal or high immune-system activity. The researcher concluded from this experiment that the immune system protects against mental illness as well as against physical disease.
The researcher's conclusion would be most seriously weakened if it were true that
(A) there was a one-year delay between the completion of a pilot study for the experiment and the initiation of the experiment itself
(B) people's levels of immune-system activity are not affected by their use of medications
(C) a few people with high immune-system activity had scores on the test of mental health that were similar to the scores of people who had normal immune-system activity
(D) people who have low immune-system activity tend to contract more viral infections than do people with normal or high immune-system activity
(E) high levels of stress first cause mental illness and then cause decreased immune-system activity in normal individuals
The researcher's conclusion depends on which of the following assumptions?
(A) High immune-system activity protects against mental illness better than normal immune-system activity does.
(B) Mental illness is similar to physical disease in its effects on body system.
(C) People with high immune-system activity cannot develop mental illness.
(D) Mental illness does not cause people's immune-system activity to decrease.
(E) Psychological treatment of mental illness is not as effective as is medical treatment.
Seven countries signed a treaty binding each of them to perform specified actions on a certain fixed date, with the actions of each conditional on simultaneous action taken by the other countries. Each country was also to notify the six other countries when it had completed its action.The simultaneous-action provision of the treaty leaves open the possibility that
(A) the compliance date was subject to postponement, according to the terms of the treaty
(B) one of the countries might not be required to make any changes or take any steps in order to comply with the treaty, whereas all the other countries are so required
(C) each country might have a well-founded excuse, based on the provision, for its own lack of compliance
(D) the treaty specified that the signal for one of the countries to initiate action was notification by the other countries that they had completed action
(E) there was ambiguity with respect to the date after which all actions contemplated in the treaty are to be complete
In January there was a large drop in the number of new houses sold, because interest rates for mortgages were falling and many consumers were waiting to see how low the rates would go. This large sales drop was accompanied by a sharp rise in the average price of new houses sold.Which of the following, if true, best explains the sharp rise in the average price of new houses?
(A) Sales of higher-priced houses were unaffected by the sales drop because their purchasers have fewer constraints limiting the total amount they pay.
(B) Labor agreements of builders with construction unions are not due to expire until the next January.
(C) The prices of new houses have been rising slowly over the past three years because there is an increasing shortage of housing.
(D) There was a greater amount of moderate-priced housing available for resale by owners during January than in the preceding three months.
(E) Interest rates for home mortgages are expected to rise sharply later in the year if predictions of increased business activity in general prove to be accurate.
The value of a product is determined by the ratio of its quality to its price. The higher the value of a product, the better will be its competitive position. Therefore, either increasing the quality or lowering the price of a given product will increase the likelihood that consumer will select that product rather than a competing one.Which of the following, if true, would most strengthen the conclusion drawn above?
(A) It is possible to increase both the quality and the price of a product without changing its competitive position.
(B) For certain segments of the population of consumers, higher-priced brands of some product lines are preferred to the lower-priced brands.
(C) Competing products often try to appeal to different segments of the population of consumers.
(D) The competitive position of a product can be affected by such factors as advertising and brand loyalty.
(E) Consumers' perceptions of the quality of a product are based on the actual quality of the product.
上面是2012GMAT逻辑推理训练，希望对考生备考有所帮助。
