[单项选择]

Americans smoke six thousand million cigarettes every year, that is, every person smokes about 4,195 cigarettes a year in the country of 18 years of age or more. It has been calculated that 51% of American men smoke while 34% of American women do so.
Since 1939, scientific studies have shown that smoking does great harm to one’s health and it will shorten one’s life.
Cigarette smoking is believed, by most research workers in the field, a very important cause in the development of the cancer of the lungs and the cancer of the throat and is believed to have much to do with some other kinds of cancers. Cigarette smokers suffer from the illness of the heart more often than those who don’t smoke. But strange, yet true, women are thought to be less affected, because when women smoke, they usually don’t breathe in the smoke so deeply. Most of doctors and researchers say, "Give up smoking. If you don’t smoke--don’t start!"
A. Americans
B. American men
C. American women
D. American aged 18 or more

[单项选择] Americans smoke six thousand million cigarettes every year (1970 figures). This is roughly the equivalent of 4,195 cigarettes a year for every person in the country of 18 years of age or more. It is estimated that 51% of American men smoke compared with 340,6 of American women. Since 1939, numerous scientific studies have been conducted to determine whether smoking is a health hazard. The trend of the evidence has been consisted and 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 an important factor in the development of cancer of the lungs and cancer of the throat and is believed to be related to cancer of the bladder and the oral cavity. Male cigarette smokers have a higher death rate from heart disease than non- smoking males.
A. twice as many as women smokers
B. two times as many as women smokers
C. 1.5 times as many as women smokers
D. seventeen percent less than women smokers