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传说中的汽车工业收入下降是言过其实的。虽然汽车制造商在整个行业收入中的份额实际已从两年前的65%降到了今天的50%，但是在同一时期内汽车零部件供应商的收入份额却从15%增加到20%，服务公司(例如分配商、销售商和修理商)的收入份额也从20%上升到了30%。 下面哪一项能最好地揭示为什么上面给出的统计数字自身不能提供它们要支持的结论的证据( )
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为一个大型建筑项目进行的融资是由一群银行提供的。当资金在项目完成前使用完时，银行批准了进一步的贷款。现在，随着资金再度用完而项目仍未完成，银行拒绝增加进一步的贷款，虽然没有这些贷款项目就会泡汤。 下面哪个如果正确，最好地解释了为什么银行现在的反应和它们先前在资金用完的情况下的反应不同( )
Hypertension is the medical term for persistent and sustained high blood pressure. It is one of the most (51) forms of heart disease. An understanding of blood pressure in (52) , healthy individuals is necessary in order to understand hypertension.Blood pressure is simply the force (53) against the walls of the body’s arteries (血管) as blood flows through. The force, produced primarily by the pumping (54) of the heart, is essential for the (55) of the blood and its life-supporting nutrients(营养) to all parts of the body. Every time the heart (56) , called a systole, blood pressure increases. When the heart relaxes (57) beats(diastole), the pressure decreases. The normal systolic pressure of a person at vest is between 100 to 140, and the normal diastole is 60 to 90. Blood-pressure readings are expressed by both (58) , with the systolic over the diastolic: for example, 140/90.As these ranges suggest, there is a wide (59) of blood pressure for healthy people. Also, blood pressure (60) for healthy people during different times of the day and under different. (61) . It is lower when an individual is asleep than when he is excited or exerting himself physically. Therefore, a single blood-pressure reading above 140/90 does not (62) abnormality. When the pressure is continuously (63) , a person is considered to be suffering from hypertension.Hypertension is a stealthy(隐秘的) problem: a physician can discover it easily enough, but not a patient. (64) elevations, for example, may produce headaches, dizziness, fatigue, and weakness. But the patient is not likely to (65) these symptoms as having any other source than the increased elevation. 55（）
FoodThe U. S. food supply is the most varied and abundant in the world. Americans spend a smaller share of their disposable income on food than citizens of any other country and choose from an average of 50,000 different food products on a typical outing to the supermarket. In 1994, the fowl supply provided an estimated 3,800 calories per person per day, enough to supply every American with more than one and a half times their average daily energy needs. Given this abundance, few of the Nations resources have traditionally been devoted to measuring or reducing food waste.In recent years, growing concern about hunger, resource conservation, and the environmental and economic costs associated with food waste have raised public awareness of food loss. This in turn has accelerated public and private efforts to make better use of available, food supplies by recovering safe and nutritious food that would otherwise be wasted.Of course, not all food that is lost is suitable for consumption. Some losses like the condemnation of diseased animals at the slaughtering house (屠宰场), or the discard of rotten fruit from the produce shelf at the supermarket are necessary to ensure the safetyand health of the U. S. food supply. Such foods are not recoverable for human use.Likewise, plate fragments are appropriately discarded at eating establishments out of health considerations. In addition, not all food that is lost is economically recoverable. Food recovery efforts are often limited by financial restraints that make it difficult to match recovered food with potential recipients.Nevertheless, large quantities of healthy, edible food are lost at every stage of the marketing system. Example of such losses include meats, bread, and other foods prepared by a restaurant or hotel but never served and the discard of defected or over-ripe .produce, which maybe difficult to sell out for some reasons, but are otherwise nutritious and safe. Discarding over-ripe produce is necessary for restaurants.()
High Stress May Damage Memory According to a report issued in May 1998, elderly people who have consistently high blood levels of cortisol don’t score as well on memory tests as their peers with lower levels of the stress hormone. What’s more, high levels of cortisol are also associated with shrinking of the hippocampus, a region of the brain that plays a key role in learning and memory. The findings suggest that even cortisol levels in the normal, "healthy" range can actually acceIerate brain aging. The study results "now provide substantial evidence that long-term exposure to adrenal stress hormones may promote hippocampal aging in normal elderly humans", write Nada Porter and Philip Landfield of the University of Kentucky in Lexington in their editorial. Cortisol is a hormone released in response to stress by the adrenal glands, which sit on top of the kidneys. Over a 5 to 6-year period. Dr. Sonia Lupien and his colleagues measured 24-hour cortisol levels in 51 healthy volunteers, most of whom were in their 70s. Despite wide variation in cortisol levels, the participants could be divided into three subgroups: those whose cortisol progressively increased over time and was currently high (increasing/high); those whose cortisol progressively increased over time and was currently moderate (increasing/moderate); and subjects whose cortisol decreased, but was currently moderate (decreasing/moderate). The researchers tested the volunteers’ memory on six people in the increasing/high category and five people in the decreasing/moderate group. The groups did not differ on tests of immediate memory, but the increasing/high cortisol group had other memory problems compared with those in the decreasing/moderate group. The researchers also found that the total volume of the hippocampus in those in the increasing/high group was 14% lower than those in the decreasing/moderate group, although there were no differences in other brain regions. The results suggest that " ... brain aging can be accelerated by levels of adrenal hormones that are not generally regarded as pathological and that variation within this normal range is related to variation in the rate of brain aging," write Porter and Landfield. "This further suggests that chronic stress may accelerate the worsening of hippocampus. \ Porter and Landfield’s research shows that______.
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