Researchers led by New York University neuroscientist Joseph LeDoux recently claimed to be the first scientists to erase a singl

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问题     Researchers led by New York University neuroscientist Joseph LeDoux recently claimed to be the first scientists to erase a single memory. Working with rats, LeDoux’s team first【B1】______the animals to fear both a beep and a siren【B2】______giving them an electric shock every time either of the tones sounded. Then LeDoux gave half the rats the drug U0126, which is known to【B3】______with memory storage, and replayed the beep【B4】______electric shocks.
    A day later, when LeDoux【B5】______back both tones to the rats, the animals that hadn’t been given the drug were still fearful of both sounds.【B6】______the rats that had been given the memory-blocking drug weren’t【B7】______of the beep, which they had last heard while【B8】______the influence of U0126.
    【B9】______how U0126 exerts its amnesiac effect is【B10】______, but it may block the synthesis of proteins that help strengthen【B11】______between neurons and establish memories. The opportunity for erasure【B12】______during the act of retrieving a memory, because that’s【B13】______the memory is being updated and【B14】______again for long-term storage. " Only those memories that are activated are【B15】______," LeDoux says.
    Drugs like U0126 may someday【B16】______sufferers of traumatic memories. A small group of human studies have been done on a drug called propranolol, which blocks the action of stress neurotransmitters that help【B17】______memories in the brain, but LeDoux’s work shows the【B18】______for greater precision. " You might be able to【B19】______the traumatic impact of memories in people," says LeDoux. " The good news is you wouldn’t be【B20】______off their memory bank. "
【B9】

选项 A、Eventually
B、Exactly
C、Surely
D、Similarly

答案B

解析 形容词辨析题。本空所在句承上启下,上段介绍了实验的发现,本段开始讨论记忆阻隔药物U0126发生作用的原理。根据转折词but之后的内容,研究者只是对药物发挥作用的大致方式进行了猜测,使用了表推测的情态动词may,可见对药物发挥作用的具体方式并不确知。[B]Exactly与后文的连词how连用,表示确切方式,故[B]为答案。由于文章在此处并没有收尾,也并非按时间顺序叙述某一事件,故[A]Eventually“最终”不符合文意,应排除。[D]Similarly“类似地”也易排除,因为文章并没有在此处对两个事物进行对照。而[C]Surely“无疑,必定”用于句首表示说话者对所说的内容(几乎)确信无疑,或表示对某事物感到惊奇,不符合原文意义,故也应排除。
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