gmat The price the goA recent study has provided clues to pr

gmat
The price the go
A recent study has provided clues to predator-prey dynamics in the late
Pleistocene era.Researchers compared the number of tooth fractures in
present-day carnivores with tooth fractures in carnivores that lived 36,000 to
10,000 years ago and that were preserved in the Rancho La Brea tar pits in Los
Angeles.The breakage frequencies in the extinct species were strikingly higher
than those in the present-day species.
In considering possible explanations for this finding,the researchers
dismissed demographic bias because older individuals were not overrepresented in
the fossil samples.They rejected preservational bias because a total absence of
breakage in two extinct species demonstrated that the fractures were not the
result of abrasion within the pits.They ruled out local bias because breakage
data obtained from other Pleistocene sites were similar to the La Brea data.The
explanation they consider most plausible is behavioral differences between
extinct and present-day carnivores-in particular,more contact between the teeth
of predators and the bones of prey due to more thorough consumption of carcasses
by the extinct species.Such thorough carcass consumption implies to the
researchers either that prey availability was low,at least seasonally,or that
there was intense competition over kills and a high rate of carcass theft due to
relatively high predator densities.
The passage suggests that tooth fractures in Pleistocene carnivores probably tended to occur less frequently
A during periods in which more prey were available
B at sites distant from the La Brea area
C in older individual carnivores
D in species that were not preserved as fossils
E in species that regularly stole carcasses from other species
定位在最后一句,不懂为什么定位在最后一句,tooth fractures么?最后一句不是没有提 tooth fractures么?

由于这两段话就是围绕tooth fracture 展开的,你在读题目定位的时候就不能用tooth fracture定位,题目当中的occur less frequently 才是解题关键
第一段交代背景：n年前灭绝的肉食动物牙齿磨损率 要 比现在的肉食动物的牙齿磨损率 要高得多
第二段快速浏览发现：研究者为了找到正确答案排除了三种偏见.注意三个动词dismiss,reject,rule out,和题目所问没关系,迅速跳过.直到most plausible 这里后面才要关注.
原来是behaviorial difference造成的：因为远古动物啃尸体啃得更烂~（比较重口,大意如此）
为啥啃得烂呢,注意这里Such thorough carcass consumption implies to the researchers either...or...either or提示你两个解释：要么没啥东西吃,要么捕食者太多,竞争激烈
题目当中的陷阱在于：假设远古时代捕食者牙齿磨损率没有那么高（less frequently）,会因为什么呢?自然就和文章最后结论相反咯--》吃的东西多了呗 （就不用那么苦逼的去嚼啊嚼,吃了上顿没下顿）
所以这个题目比较狡猾.读题目的时候就要小心less frequently 和第一段的结论strikingly higher相反,那就要赶紧找到造成strikingly higher的结论（由文中implies 引导）的第一点：availability was lows,答案和这句话相对应(more available),只不过取了反义词而已
简单来说就是:牙齿磨损高