Between now (June) and Labour Day, millions of Americans will offer up their bodies to the sun’s rays. A an indicates health and beauty, and most sun worshippers will sacrifice ( 牺牲 ) lot to achieve it including themselves. With each hour, the sun’s ultraviolet (紫外线 ) radiation produces irreversible ( 不可逆的) damage, hastening the development of unsightly wrinkles. And with each year on the beach or rooftop, the sunbather increases his risk of getting skin cancer.

Skin cancer is by far the most common form of cancer. An estimated 400,000 new cases will be detected this year in the US, and almost all of them can be blamed on overexposure to the sun. Fortunately, most of these cancers are highly curable. But they can be disfiguring and take time to treat. For that reason, sun worshippers should treat deity with a good deal of awe.

Sunburn, of course, is the initial danger posed by UV radiation. Prolonged exposure to UV, however, interferes with the production of collagen fibres in the dermis, causing the skin to lose elasticity and creating premature wrinkles. Further damage of the dermis deprives the epidermis of nutrition and causes it to become thin and dry.

Cancer is UV’s final insult. Short-wave radiant energy, especially from the UV-B band, breaks the strands of DNA. Enzymes works constantly to rearrange the DNA into proper sequence, but with repeated UV exposure, the repair process may eventually break down. Then DNA may produce a colony of cancer cells.

But skin cancer may be avoided with a good dose of common sense. People with fair skin and blue eyes who burn easily stand the highest risk. Special danger spots are the parts of the body most constantly exposed to the sun, such s the cheeks, nose, lower lip and the ears. People who have already had one skin-cancer growth stand a greatly increased chance of developing others. People are recommended avoiding the sun when it is most intense between 11am and 3 pm. Anyone who insists on sunbathing should use a good sun screen. These lotions contain chemicals that block out the burning UV-B radiation while permitting the tanning rays to reach the skin.

1.According to the passage, overexposure to the sun may result in ________.

A.the wrinkles that cannot be seen  B. the skin cancer

C.all kinds of sacrifices        D. healthful beauty

2The word “deity” in the second paragraph refers to ________.

A.something mysterious       B. the skin cancer

C.the sun              D. overexposure to the sun

3.Which of the following comes first as a possible damage by UV radiation?

A.Sunburn              B. The loss of skin elasticity.

C.Dryness of epidermis        D The damage of dermis

4.Why does the repair process of the DNA may finally fail?

A.Because short-wave radiant energy breaks the strands of the DNA.

B.Because the DNA may produce a colony of cancer cells.

C.Because enzymes work to rearrange the DNA into a new order.

D.Because the patient is exposed to UV from time to time.

5.The last paragraph of the passage mainly discuss _______.

A.the treatment of the cancer

B.the prevention of the skin cancer

C.the parts of the body where cancer is most likely to develop

D.the lotions that work best in fighting against the skin cancer

 

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