单选题 Does caffeine affect the heart? In 1972 and 1973 Dr. Hershel Jick and fellow researchers at the Boston University Medical Center published two studies on coffee and myocardial infarction, the most common type of heart attack. They concluded that people who drank one to five cups of coffee daily ran a 50-percent greater risk of heart attack than those who drank no coffee, and that those who drank six or more cups daily were at ll0-percent greater risk. On the surface this made sense, for coffee can influence pulse rate and blood pressure.
But other scientists criticized Jick and questioned his methods of selecting subjects for the study. They noted that Jick had found no link between myocardial infarction and the drinking of tea, which also contains caffeine. And they asked why he had overlooked the possibility that heavy coffee drinking and heart problems might both be results of certain personality traits.
Other major studies contradicted Jick's findings. In the Framingham heart-disease epidemiology study, researchers began in 1949 to monitor more than 5 100 citizens of the Massachusetts town. They found no link between coffee consumption sumption and heart problems. A similar study on 2 500 Georgia residents and another on 1 700 men in Chicago also failed to connect heart disease and coffee drinking. Dr. Jick's studies have been interpreted by other scientists to show that coffee drinkers are more likely to survive a heart attack than are non-drinkers, because caffeine acts as a mild stimulant.
For people with arrhythmia(irregularity of heartbeat), coffee drinking should be approved by a physician, because heavy doses of caffeine can alter heart rhythms. Those with high blood pressure should also consult their doctors because caffeine might raise that pressure. Several studies on laboratory animals have found evidence that caffeine can elevate the level of free fatty acids, lipids and cholesterol in the blood. But most of the major studies find little or no link between heart disease and coffee drinking.

单选题 Dr. Hershel Jick and his fellow researchers made two studies and concluded that ______.
A. the more coffee people drink the more possibility they would have to suffer from heart attack
B. people who drank no coffee would suffer from heart attack
C. people who drank one or two cups of coffee every day would probably run 50-percent greater risk of heart attack
D. people who drank six or seven cups every day would be at 110percent greater risk

单选题 Some scientists thought Jick ______.
A. exaggerated his findings
B. made a serious mistake in his studies
C. had noticed the real reason of heart disease
D. neglected the personal characters which can cause heart disease

单选题 Which of the studies contradicted Jick's results? ______.
A. A research began in 1949.
B. A study in Massachusetts town.
C. A study in Georgia and Chicago.
D. All above.

单选题 Some major studies made by other scientists found that ______.
A. coffee drinking can cause arrhythima
B. coffee drinking can cause high blood pressure
C. coffin can raise the level of free fatty acids, lipids and cholesterol in people's blood
D. there is little or no link between heart attack and coffee drinking

单选题 According to this text, coffeine can ______.
A. affect the heart
B. not affect the heart
C. affect just the most common type of heart attack
D. sometimes affect the people who have suffered from high blood pressure