Vitamin D helps bones and muscles grow strong and healthy. Low levels of vitamin D can lea

Vitamin D helps bones and muscles grow strong and healthy. Low levels of vitamin D can lead to diseases such as rickets (佝偻病), mainly found in children. The thinning of bone is a common problem as people, especially women, get older.
But more and more research is suggesting that vitamin D might also help prevent many diseases. The easiest way to get vitamin D is from sunlight. The sun’s ultraviolet (紫外线的) rays react with skin cells to produce vitamin D. But many people worry about getting skin cancer and skin damage from the sun. As a result they stay out of the sun. Also, darker-skinned people produce less vitamin D than lighter-skinned people. The amount also decreases in older people and those living in northern areas that get less sunlight.
Not many foods naturally contain vitamin D. Foods high in this vitamin include oily fish and fish liveroils (鱼肝油). Farmed fish have only about one-fourth as much vitamin D as wild fish. Small amounts of vitamin D are found in beef liver, cheese and egg yolks. But most of the vitamin D in the American diet comes from foods such as milk.
Research in the last several years has shown that low levels of vitamin D may increase the risk of heart attacks in men and deaths from some cancers. More doctors are now having their patients tested for their vitamin D levels. But as research continues, some experts worry that if people take too much vitamin D, it might act as a poison. Also, skin doctors warn people to be careful with sun exposure because of the risk of skin cancer.
【小题1】The first paragraph is mainly about .A．the muscle diseasesB．the sources of vitaminsC．the importance of healthD．the functions of vitamin D【小题2】Which of the following people produce the least amount of vitamin D? A．Elderly darker-skinned people.B．Young lighter-skinned people.C．Elderly lighter-skinned people.D．Young darker-skinned people.【小题3】 People can get the most vitamin D from .A．beef liverB．cheeseC．wild fishD．farmed fish【小题4】What can we infer from the text?
A. Being exposed to sunlight is the safest way to get vitamin D.
B. Lack of vitamin D can make people age quickly.
C. Proper vitamin D levels people need are still not determined now.
D. The vitamin D level is higher in men than in women.D

(答案→)D 解析：【小题1】从第一段第一行Vitamin D helps bones and muscles grow strong and healthy维他命D使骨头和肌肉强壮，健康结合后面缺乏维他命D会导致一些疾病可得知第一段主要讲Vitamin D的功能。、【小题2】从第二段darker-skinned people produce less vitamin D than lighter-skinned people. The amount also decreases in older people可知年老深色皮肤的人产生的Vitamin D最少。【小题3】从第三段Foods high in this vitamin include oily fish and fish liveroils (鱼肝油)Farmed fish.。。。found in beef liver, cheese and egg yolks比较得出Farmed fish里Vitamin D最丰富。【小题4】推断题。从第二段The easiest way to get vitamin D is from sunlight可看出A答案表达错误。Ｂ答案是直接信息，不能入选，Ｄ答案未提及，故选Ｃ

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