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题目： On a given day, 50 people took a test that is designed to measure a candidate's aptitude. Some of the 50 people will take the test in the morning, and the remaining of the 50 people will take the test in the afternoon. What is the average (arithmetic mean) score on the test for the 50 examinees?(1) The average score for the examinees who take the test in the morning was 68.2.(2) The average score for the examinees who take the test in the afternoon was 74.3.

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Sunflowers growing in pots were placed, with their roots submerged, in the pond contaminated with radioactive elements. The sunflowers kept growing; in the process, they absorbed radioactive elements. Within twelve days, 85 percent of the radioactive elements were removed from the water, which is no less than can be accomplished with the much more expensive conventional filtration techniques. Scientists therefore propose using sunflowers for decontamination wherever there are radioactively contaminated ponds.

Which of the following, if true, points to a limitation on the applicability of the proposed method of decontamination?

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During the summer of 1778, seeking to find alternative explanations for the process of evolution, Jean-Baptiste Lamarck repeated his initial experiment on mollusks once in every 4 weeks but received exactly the same results 3 times in a row.

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The soap manufacturer conceded that its product may have contributed to the recent outbreak of skin irritation experienced by its consumers and having pulled the product, led to a sharp drop in the company's share price.

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题目： Even-toed ungulates, including pigs, cattle, goats, and sheep, and odd-toed ungulates, such as horses and donkeys, account for all the mammals domesticated for agricultural purposes.

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题目： While many people believe either lead or gold is the densest naturally occurring element, osmium, due to a pattern of density among the elements, holds this distinction, and they call it "Lathanide contraction."

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Seldom more than 40 feet wide and 12 feet deep, but it ran 363 miles across the rugged wilderness of upstate New York, the Erie Canal connected the Hudson River at Albany to the Great Lakes at Buffalo, providing the port of New York City with a direct water link to the heartland of the North American continent.

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Concerns about public health led to the construction between 1876 and 1904 of three separate sewer systems to serve metropolitan Boston.

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题目： Most insomnia is not an illness or a physical condition so much as a symptom of another problem that may simply be a reaction to certain medications, anxiety about travel, or stress before a job interview.

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题目： Researchers are using computer images to help surgeons plan difficult operations and to develop programs that will work for doctors and nurses in the same way that flight simulators do for pilots, letting medical personnel practice their techniques and test their reflexes before they ever see a patient.

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In the past, most children who went sledding in the winter snow in Verland used wooden sleds with runners and steering bars. Ten years ago, smooth plastic sleds became popular; they go faster than wooden sleds but are harder to steer and slow. The concern that plastic sleds are more dangerous is clearly borne out by the fact that the number of children injured while sledding was much higher last winter than it was ten years ago.

Which of the following, if true in Verland, most seriously undermines the force of the evidence cited?

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题目： SafeZone mosquito repellant has been shown in laboratory settings to be effective for twelve hours against the female anopheles mosquito, the only mosquito that transmits malaria. SafeZone, however, is not effective against mosquitoes that do not transmit malaria. The only instance in which SafeZone does not repel the female anopheles mosquito is when this mosquito can detect any ruptured blood vessels, a state that inevitably results whenever any kind of mosquito bites a person. Therefore, assuming one does not have any ruptured blood vessels on their skin before applying SafeZone, that person will not be able to catch malaria for up to twelve hours.Which of the following, if true, would argue most against the use of SafeZone in areas in which malaria is endemic?

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题目： Nearly all employees of the factory who have completed their high school diploma have earned their factory safety certificate, having easily completed the eight week training course. The high school graduates who haven't earned the certificate are ones who have evening obligations that have prevented them from taking the course. Overall, though, most of the factory workers have not earned the certificate. If the statements above are true, which one of the following also must be true?

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题目： During the period in which there are no competitive races, two runners--Runners A and Runners B--take part in an experiment measuring their VO2 max, the volume of oxygen an athlete can use. During these sessions, the runners engaged in moderate aerobic activity, or a sustained heart rate between 146-154 beats per minute. At the end of the sessions, Runner A had a greater VO2 max than did Runner B. Therefore, once the two runners begin identical intensive training--sessions involving over 168 beats per minute-- for the race season, Runner A will continue to have the greater VO2 max, assuming that neither become injured and that both train with similar intensity.Which of the following is an assumption upon which the argument rests?

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题目：

The passage suggests that lagging indicators would be least helpful in determining which of the following?