2. 外语
  3. An anesthetic is anything that produces a temporary loss of feeling in all or part of the body. Anesthetics are given to those a

An anesthetic is anything that produces a temporary loss of feeling in all or part of the body. Anesthetics are given to those a

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问题     An anesthetic is anything that produces a temporary loss of feeling in all or part of the body. Anesthetics are given to those about to undergo surgery or other painful medical procedures so that they will feel no pain. This also helps the doctors do their job. The patient remains still during the operation.
    Imagine the horror of having to go through an operation wide awake, with nothing to stop the pain! This is what faced people before the discovery of modem anesthetics in the nineteenth century. Until then doctors and others had tried to anesthetize patients by every means from drugging them or making them drunk to hitting them on the head. Then in the 1940s two American doctors, Crawford Long and William Morton proved that patients who breathed a certain amount of a gas called ether would remain unconscious, unmoving, and unfeeling for the length of an operation. They would not be subject to agony.
    Today medical specialists called anesthesiologists employ gases such as nitrous oxide("laughing gas"), or injected drugs. Sometimes both are administered. These anesthetics keep patients unconscious for the many hours some complex operations require. For major operations, a general anesthetic is usual. The patient is given a gas or drug that is absorbed by the blood, which then circulates it to the nervous system. As the anesthetic numbs the central nervous system, the body of the person undergoing surgery relaxes and ceases to feel.
    Some operations, however, require only a local anesthetic. This consists of a drug injected into the area to be operated on, to deaden the local nerves. Only that particular part of the body is affected. If your dentist has ever given you novocaine before pulling or filling a tooth, you have experienced local anesthesia.
    A third type of anesthetic is the spinal. An injection of a drug into the spinal cord, which runs along the backbone, completely desensitizes nerves and relaxes muscles in all parts of the body below the point of injection. The patient doesn’t feel anything. He or she is spared severe pain.
Some operations require only a local anesthetic in which______.
选项 A、you have your teeth pulled or filled
B、a drug is injected only into the area to be operated on
C、you will receive novocaine
D、both gases and drugs are to be used
答案B
解析 文章指出，部分手术只需要局部麻醉，这种麻醉剂含有一种能直接注射到实施手术的区域物质，以麻醉神经。第四段Some operations，however，require only a local anesthetic．This consists of adrug injected into the area to be operated on，to deaden the local nerves．
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