单项选择题

In 1976 more than 500 people contracted an autoimmune disease called Guillain - Barresyndrome after receiving swine - flu shots in response to a small outbreak in Fort Dix, N. J. Some people understandably fear a repeat of that tragic episode, However, vaccine, production techniques have changed since then. Today, vaccines are highly purified to eliminate any potential contaminants. In addition, scientists use only selected viral proteins in the shots, not the entire virus, as they did in the 1970s. "The public is comparing this vaccine to the 1976 swine--flu vaccine," says CDC spokesperson Abbigail Tumpey. "In fact, the best comparison is to the seasonal vaccines of the last ten years. "
Nowadays ,vaccines are highly purified to

A. remove people’s fear for vaccine.
B. avoid repeating the tragic episode in 1976.
C. get rid of any possible contaminants.
D. improve vaccine -production techniques.

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单项选择题Since 1939, numerous studies have been conducted to determine whether smoking is a health hazard. The trend of the evidence has been consistent and indicates that there is a serious health risk. Research teams have conducted studies that show beyond all reasonable doubt that tobacco smoking is associated with a shortened life expectancy. Cigarette smoking is believed by most research workers in this field to be an important factorin the development of caner of the lungs and cancer of the throat and is believed to be related to cancer of some other organs of the body. Male cigarette smokers have a higher death rate from bean disease than non--smoking males. Female smokers are thought to be less affected because they do not breathe in the smoke so deeply.

Apart from statistics, it might be helpful to look at what smoking tobacco does to the human body. Smoke is a mixture of gases, vaporized chemicals, minute particles of ash and other solids. There is also nicotine, which is powerful poison, and black tar. As smoke is breathed in, all those components from deposits on the membranes of the lungs. One point of concentration is where the air tube and bronchus divides. Most lung cancer begins at this point.
Filters and low tar tobacco are claimed to make smoking to some extent safer, but they can only slightly reduce, not eliminate the hazards.
What is the main idea of the passageA. Smoking is big hazard to health.
B. There are ways to make smoking safe.
C. Smoking is more hazardous to male smokers than to female smokers.
D. There are many poisonous chemicals in tobacco.

单项选择题Davies is an official of the Saskatchewan Medical Society, so it’s not surprising that he would want to extol Canadian medicine. But that feeling of patriotic pride in the nation’s health - care system is something that just about all Canadians share. They love to point out that Canada provides coverage for everybody, usually with no copay and no deductible--while the U. S. leaves tens of millions of its citizens uninsured. They love to remind US that, while the U. S. lets some 700,000 people go bankrupt due to medical bills each year, the number of medicalbankruptcies in Canada is precisely zero.

Almost all Canadians are proud of the fact thatA. Canada’s health - care system covers every one of its citizens.
B. many people go bankrupt each year due to medial bills.
C. many people are not included in the health - care system.
D. people have to wait for a long time for medical treatment.