2. 考研
  3. Antibiotics, before they became used as drugs, were natural products. A new finding provides the first direct【C1】______that anti

Antibiotics, before they became used as drugs, were natural products. A new finding provides the first direct【C1】______that anti

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问题     Antibiotics, before they became used as drugs, were natural products. A new finding provides the first direct【C1】______that antibiotic resistance is a widespread natural phenomenon that【C2】______the modern medical use of antibiotics. Experts had long predicted this on theoretical【C3】______, but they say the new finding【C4】______the need to use antibiotics sparingly, 【C5】______that the genes for antibiotic resistance are very common and can easily be【C6】______by antibiotics. "The fact that the genes for resistance are so ancient and widespread means there is no easy【C7】______to the problem of resistance — we will never invent a super-antibiotic that【C8】______everything up," said Martin J. Blaser, a microbiologist at New York University.
    Antibiotics are substances【C9】______by fungi, algae and bacteria for signaling and for defense. The inhabitants of this microbial world have also evolved genes that【C10】______antibiotics. After millions of years of chemical【C11】______, two classes of sophisticated genes have【C12】______, those that make antibiotics and those that provide resistance to antibiotics. "Antibiotic resistance is part of the natural ecology of the planet, and this finding is a【C13】______note about how we use these things," Dr. Wright said. "Antibiotics are remarkable resources that need to be carefully【C14】______. "
    Widespread use of the drugs has stimulated the【C15】______of bacteria that have become the 【C16】______of hospitals because they can resist many different kinds of antibiotic. "What this finding says to me is that we have to use the antibiotics we have【C17】______, because we’re not going to【C18】______misuse," said Stuart Levy, a microbiologist at Tufts University who has【C19】______of wasteful use of antibiotics for 30 years. "What had been missed in the 1960s and 1970s was the【C20】______with which resistance could appear," he said. "Bacteria share these genes like baseball cards with each other. "[308 words]
【C12】
选项 A、disappeared
B、emerged
C、merged
D、divided
答案B
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考研英语一

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