雅思阅读真题（Part 2）
Part 2 · 考频：高频 · 最近考试：2025.4.26/2019.3.23/2018.2.3/2013.5.18
A
The ants and their agriculture have been extensively studied over the years, but the recent research has uncovered intriguing new findings about the fungus they cultivate,how they domesticated it and how they cultivate it and preserve it from pathogens.For example,the fungus farms,which the ants were thought to keep free of pathogens,turn out to be vulnerable to a devastating mold,found nowhere else but in ants’ nests.To keep the mold in check,the ants long ago made a discovery that would do credit to any pharmaceutical laboratory.
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答案：A Leaf-cutting ants
原文定位：the leaf-cutters use fresh vegetation;because it allows them to eat, courtesy of their mushroom’s digestive powers, the otherwise poisoned harvest of tropical forests whose leaves are laden with terpenoids, alkaloids and other chemicals designed to sicken browsers
答案：B Lower attine ants
原文定位：the other groups, known as the lower attines because their nests are smaller and their techniques more primitive, feed their gardens with detritus like dead leaves, insects and feces;the lower attine ants used different varieties of the fungus, and in one case a quite separate species
答案：B Lower attine ants
原文定位：The leaf-cutters use fresh vegetation; the other groups, known as the lower attines because their nests are smaller and their techniques more primitive, feed their gardens with detritus like dead leaves, insects and feces
答案：A Leaf-cutting ants
原文定位：The leaf-cutters’ fungus was indeed descended from a single strain, propagated clonally, or just by budding, for at least 23 million years;It seems that the price they pay for cultivating a pure variety of fungus is a higher risk from Escovopsis
答案：A Leaf-cutting ants
原文定位：Evidently the ants usually manage to keep Escovopsis and other parasites under control;within two years some 60 percent become infected;Mr. Currie found that the leaf-cutters had in general fewer alien molds in their gardens than the lower attines, yet they had more Escovopsis infections
答案：C Both leaf-cutting ants and lower attine ants
原文定位：There is now a possible reason to explain why the lower attine species keep changing the variety of fungus in their mushroom gardens, and occasionally domesticating new ones-to stay one step ahead of the relentless Escovopsis;Mr.Currie discovered a specialised patch on the ants’ cuticle that harbours a particular kind of bacterium;The Streptomyces does not have much effect on ordinary laboratory funguses. But it is a potent poisoner of Escovopsis;Because both the leaf-cutters and the lower attines use Streptomyces
答案：E
原文定位：Escovopsis turns out to be a highly virulent pathogen that can devastate a fungus garden in a couple of days;In a day or two the whole garden is enveloped. “Other ants won’t go near it and the ants associated with the garden just starve to death,” Dr. Rehner said. “They just seem to give up, except for those that have rescued their larvae
答案：D
原文定位：Mr.Currie,resembled the monocultures of various human crops, that are very productive for a while and then succumb to some disastrous pathogen, such as the Irish potato blight.Monocultures,which lack the genetic diversity to respond to changing environmental threats,are sitting ducks for parasites
答案：C
原文定位：The leaf-cutters use fresh vegetation; the other groups, known as the lower attines because their nests are smaller and their techniques more primitive, feed their gardens with detritus like dead leaves, insects and feces
答案：H
原文定位：If so, some Alexander Fleming of an ant discovered antibiotics millions of years before people did. Even now, the ants are accomplishing two feats beyond the powers of human technology.The leaf-cutters are growing a monocultural crop year after year without disaster, and they are using an antibiotic apparently so wisely and prudently that, unlike people, they are not provoking antibiotic resistance in the target pathogen
答案：F
原文定位：There is now a possible reason to explain why the lower attine species keep changing the variety of fungus in their mushroom gardens, and occasionally domesticating new ones-to stay one step ahead of the relentless Escovopsis
答案：His viewpoint was verified later.
原文定位：Mr.Currie felt there had to be a parasite in the ant-fungus system. But a century of ant research offered no support for the idea. Textbooks describe how leaf-cutter ants scrupulously weed their gardens of all foreign organisms;But after three years of sifting through attine ant gardens, Mr.Currie discovered they are far from free of infections;he and two colleagues;isolated several alien organisms, particularly a family of parasitic molds called Escovopsis
答案：a substance which is useful to humans
原文定位：Mr.Currie discovered a specialised patch on the ants’ cuticle that harbours a particular kind of bacterium, one well known to the pharmaceutical industry, because it is the source of half the antibiotics used in medicine;The Streptomyces does not have much effect on ordinary laboratory funguses. But it is a potent poisoner of Escovopsis, inhibiting its growth and suppressing spore formation