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  3. Now medical researchers are discovering a truism: "alcohol and tobacco do not mix." These two substances, both dangerous to heal

Now medical researchers are discovering a truism: "alcohol and tobacco do not mix." These two substances, both dangerous to heal

admin2014-02-27  69
问题     Now medical researchers are discovering a truism: "alcohol and tobacco do not mix." These two substances, both dangerous to health, act synergistically, each making the other more powerful and thereby causing worse damage than either would do alone.
    Because of this interaction, the person who both smokes and drinks heavily may be at a greater risk of becoming ill than one who drinks like a fish, but never smokes or who smokes like a chimney, but never drinks. To get an idea of how this synergism may work, consider what happens when a smoker lights up a cigarette. With each puff he inhales at least 4,000 different chemicals. These include toxic hydrogen-cyanide, carbon monoxide and nitrogen-dioxide gases, and four dozen compounds such as benzo pyrene and radioactive polonium 210. All are known as carcinogens. Most chemical vapors in tobacco smoke get deposited in the mouth, nose, throat and lungs in a coating called tar. It is in this tar that most of the cancer — inducing potential of tobacco smoke lies. Then in a scenario typical of chronic heavy drinkers — most of whom also smoke — our smoker feels thirsty and washes down that smoke coating in his mouth and throat with whisky. The alcohol in his drink is not in itself a carcinogen, but it may act as a solvent, dissolving the tar-taped tobacco poisons, and easing the transport of carcinogens across membranes.
    Our smoker continues to drink. Soon he lights another cigarette and inhales deeply. Behind his embattled lungs, meanwhile, his liver has gone on full alert to save his life. The three-pound chemical factory, which cleans most toxins from the bloodstream, reacts to alcohol as a foreign substance and metabolizes 95 percent of it into other chemicals. But in turning its energy to clearing just one-half ounce of pure alcohol — the amount in a standard drink — per hour from our drinking smoker’s blood, the liver’s other metabolic functions suffer a sharp decrease. Poisons from tobacco smoke that otherwise would be removed from his blood within minutes are now allowed to flood his body for hours or days, depending on how much alcohol the liver must dispose of.
    The person who smokes one or two packs of cigarettes a day loses on average six to eight percent of his blood’s oxygen carrying capacity. If our heavy smoker’s use of alcohol has led to alcoholism, he is probably malnourished. This malnourishment compounds problems he is having with insufficient oxygen. His brain cells are dying from it.
    The synergistic effect of alcohol and tobacco may deliver a powerful blow to the cardiovascular system as well as the upper respiratory tract. For those prone to hypertension who drink more than two ounces of alcohol a day, high blood pressure is common and with it the increased risk of stroke and heart attack. For hypertensives who combine smoking and drinking, the risks are even greater.
The reason why the brain cells of the person who both smokes and drinks heavily are dying is that______.
选项 A、smoking reduces the oxygen carrying capacity of his blood
B、smoking and drinking make him malnourished
C、the problem of deficient oxygen supply and malnourishment act synergistically
D、it’s the normal metabolism
答案C
解析 这是一道细节题。文章第四段指出：如果嗜烟者因喝酒而导致酒精中毒，那么他很可能会营养不良；这种营养不良与他已有的缺氧问题结合，他的脑细胞就会因此而逐步死亡。这说明，C“供氧不足和营养不良相互作用”，与文章的意思符合。A和B只是部分原因，不全面；文中没有提到D。
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