職稱英語衛生類AB級：閱讀理解Smoking and Cancer

　　Americans smoke six thousands million cigarettes every year (1970 figures). This is roughly the equivalent of 4195 cigarettes a year for every person in the country of 18 years of age or more. It is estimated that 51 % of American men s moke compared with 34 % of American women. Since 1939， numerous scientific studies have been conducted to determine whe ther smoking is a health hazard. The trend of the evidence has been consistent a nd indicates that there is a serious health risk. Research teams have conducted studies that show beyond all reasonable doubt that tobacco smoking， particularly cigarette smoking is associated with a shortened life expectancy. Cigarette smoking is believed by most research workers in this field to be a n important factor in the development of cancer of the lungs and cancer of the t hroat. Male cigarette smokers have a higher death rate from heart disease than O n-smoking males. Female smokers are thought to be less affected because they do not breathe in the smoke so deeply. The majority of physicians and researchers consider these relationships proved to their satisfaction and say， ’Give up smoking！ If you don’t smoke， don’t start！ ’ . It might be helpful to look at what tobacco-smoking actually does to the hum an body. Smoke is a mixture of gases， vaporized chemicals， minute particles of a sh， and other solids. There is also nicotine， which is a powerful poison， and bl ack tar. As the smoke is breathed in， all these components form deposits on the membranes of the lungs. One point of concentration of deposits is where the air tube divides. Most lung cancer begins at this point. Smoking also affects the heart and blood vessels. It is known to be related to Beurger’s disease， a narrowing of the small veins in the hands and feet that can cause great pain. Smokers also die much more often from heart disease. While all tobacco-smoking affects life expectancy and health， cigarette smok ing appears to have a much greater effect than cigar or pipe smoking. However， n icotine consumption is not diminished by the latter forms， and current research indicates a causal relationship between all forms of smoking and cancer of the m outh and throat. Filters and low tar tobacco are claimed to make smoking to some extent safer， but they can only marginally reduce， not eliminate the hazards.

　　41、Which of the following statements is NOT true according to the info rmation given in the passage? ____

　　A.Tobacco smoking can cause life-shortening diseases.

　　B.There are twice as many men smokers as women smokers in the U. S. According to the 1970 figures.

　　C.Filters can only decrease rather than eliminate the harm to the human body.

　　D.In the smoke there is nicotine which is an important factor in the development of cancer of some organs.

　　42、(同41題)The statement "be associated with a shortened life expectancy" in the s***nd aragraph signifies____

　　A.\！cause a life expectancy to shorten".

　　B.\！be caused by a shortened life expectancy".

　　C.\！will change with the shortened life expectancy".

　　D.\！will cause from the shortened life expectancy".

　　43、(同41題)Female smokers are probably less affected by heart disease because____

　　A.cigarettes women smoke are treated in a special way.

　　B.tissue of the heart can get rid of the poisonous elements.

　　C.they inhale the smoke less deeply.

　　D.they， in most cases， pretend to be smokers.

　　44、(同41題)Tobacco smoke is a mixture____

　　A.of two poisonous elements.

　　B.of various poisonous substances.

　　C.of some irritant gases.

　　D.of carbon dioxide and water vapour.

　　45、(同41題)Harmfulness from all forms of smoking to the human body may be arranged in severity sequence as follows:____

　　A.Cigarette smoking is put first， and next comes cigar or pipe smoking.

　　B.No 1 killer is cigar smoking， and it’s followed by cigarette or pipe smoking.

　　C.Cigar or pipe smoking has nearly no effect on the human body in contrast with igarette smoking.

　　D.All forms of smoking are similar in effect harmful to the human body.