GMAT07perp语法笔记320题.doc

GMAT 07perp 语法笔记320题1. (24179-!-item-!-188;#058&000705)Although fullerenes--spherical molecules made entirely of carbon--were first found in the laboratory, they have since been found in nature, formed in fissures of the rare mineral shungite. Since laboratory synthesis of fullerenes requires distinctive conditions of temperature and pressure, this discovery should give geologists a test case for evaluating hypotheses about the state of the Earth's crust at the time these naturally occurring fullerenes were formed.Which of the following, if true, most seriously undermines the argument?(A) Confirming that the shungite genuinely contained fullerenes took careful experimentation.(B) Some fullerenes have also been found on the remains of a small meteorite that collided with a spacecraft.(C) The mineral shungite itself contains large amounts of carbon, from which the fullerenes apparently formed.(D) The naturally occurring fullerenes are arranged in a previously unknown crystalline structure.(E) Shungite itself is formed only under distinctive conditions.2. (24227-!-item-!-188;#058&000711)Economist: On average, the emergency treatment for an elderly person for injuries resulting from a fall costs $11,000. A new therapeutic program can significantly reduce an elderly person's chances of falling. Though obviously desirable for many reasons, this treatment program will cost $12,500 and thus cannot be justified.Which of the following, if true, most seriously undermines the conclusion of the argument?(A) Among elderly people who had followed the program for only a few months, the number of serious falls reported was higher than it was for people who had followed the program for its recommended minimum length of one year.(B) Falls resulting in serious injuries are less common among elderly people living in nursing homes than they are among elderly people who live alone at home.(C) A frequent result of injuries sustained in falls is long-term pain, medication for which is not counted among the average per-person costs of emergency treatment for elderly people's injuries from such falls.(D) The new therapeutic program focuses on therapies other than medication, since overmedication can cause disorientation and hence increase the likelihood that an elderly person will have a serious fall.(E) A significant portion of the cost of the new therapeutic program is represented by regular visits by health care professionals, the costs of which tend to increase more rapidly than do those of other elements of the program.3. (24275-!-item-!-188;#058&000768)The prairie vole, a small North American grassland rodent, breeds year-round, and a group of voles living together consists primarily of an extended family, often including two or more litters. Voles commonly live in large groups from late autumn through winter; from spring through early autumn, however, most voles live in far smaller groups. The seasonal variation in group size can probably be explained by a seasonal variation in mortality among young voles.Which of the following, if true, provides the strongest support for the explanation offered?(A) It is in the spring and early summer that prairie vole communities generally contain the highest proportion of young voles.(B) Prairie vole populations vary dramatically in size from year to year.(C) The prairie vole subsists primarily on broad-leaved plants that are abundant only in spring.(D) Winters in the prairie voles' habitat are often harsh, with temperatures that drop well below freezing.(E) Snakes, a major predator of young prairie voles, are active only from spring through early autumn.4. (24323-!-item-!-188;#058&000813)A popular beach has long had a dolphin feeding program in which fish are given to dolphins several times a day; many dolphins get as much as half of their food each day there. Although dolphins that first benefit from the program as adults are healthy and long-lived, their offspring have a lower life expectancy than offspring of dolphins that feed exclusively in the wild.Which of the following, if true, most helps to explain the lower life expectancy of offspring of dolphins feeding at the beach compared to other young dolphins?(A) Sharks that prey on dolphins are less common in the open seas off the beach than in many other areas of the open seas where dolphins congregate.(B) Many of the adult dolphins that feed at the beach are females that nurse their offspring there.(C) The fish given to the dolphins at the beach are the same types of fish that dolphins typically catch in the wild.(D) Many dolphins that feed at the beach with their offspring come to the beach only a few times a month.(E) Adult dolphins that feed at the beach spend much less time teaching their offspring how to catch fish in the wild than do other adult dolphins.5. (24371-!-item-!-188;#058&000859)Tiger sharks are common in the 。