18．A healthy amount of sunshine may be the secret to staying young．British scientists have discovered．
Vitamin D is produced naturally by the skin in response to（对…的反应） sunlight and may help to slow the ageing process and protect against heart disease，according to the study．
Researchers from King's College London studied 2，160women aged between 18and 79，looking at their telomeres---a biological marker of ageing found in DNA．As people get older，their telomeres get shorter and they become more susceptible（易受伤害的） to certain illnesses．
But the study found women with high levels of vitamin D had comparatively longer telomeres---a sign of being biologically younger and healthier．
The study suggests vitamin D may help to slow down the ageing（变老，老化） process of DNA，and therefore the ageing process as a whole．
Lead researcher Dr Brent Richards said，"These results are exciting because they show for the first time that people who have higher levels of vitamin D may age more slowly than people with lower levels of vitamin D．"This could help to explain how vitamin D has a protective effect on many ageing related diseases，such as heart disease and cancer．"
Professor Tim Spector，a co-author of the report，added，"Although it might sound absurd（荒唐的），it's possible that the same sunshine which may increase our risk of skin cancer may also have a healthy effect on the general ageing process．
Vitamin D made by the action of sunlight on the skin accounts for 90percent of the body's supply，but lower levels can also be got through food such as fish，eggs and breakfast cereals（粥）．
Other studies have suggested the vitamin plays a key role in protecting against cancer and heart disease．
25．A certain amount of sunshine helps people stay young becauseD．
A．people feel happy and energetic in the sun
B．sunshine protects people against heart disease
C．vitamin D makes one's skin look young and healthy
D．vitamin D may help to slow the ageing process．
26．From Brent Richards，we know thatD．
A．sunlight causes skin cancer to people with high level of vitamin D
B．the study generally has a healthy effect on the general ageing process
C．vitamin D can only be got from fish，eggs and breakfast cereals
D．the higher levels of vitamin D people have，the more slowly people may age
27．What can we infer from the passage？C
A．Telomeres are important as they are signs of ageing of the DNA．
B．Sunlight can be dangerous as it causes skin cancer．
C．Sunlight does more good than harm to our health．
D．Vitamin D can also be gained from food．
28．What is the best title of the passage？B
A．Secret of Staying Young
B．Vitamin D Helps Slow Ageing
C．Sunlight and Vitamin D
D．Sunlight and Health．
分析 本文主要讲的是研究表明太阳光产生的维他命D能够延缓衰老，从而使人保持年轻．
解答 25-28．DDCB
25题答案：D 考查细节推理，根据文章第二段的Vitamin D is produced naturally by the skin in response to（对…的反应） sunlight and may help to slow the ageing process and protect against heart disease（作为对阳光的自然反应而产生的维他命D可能有助于减缓老化过程以及保护我们抵抗心脏病）可知本题答案为D选项．
26题答案：D 考查细节推理，根据文章第六段的These results are exciting because they show for the first time that people who have higher levels of vitamin D may age more slowly than people with lower levels of vitamin D（这些结果很令人兴奋，因为它们首次展示了维他命D水平更高的人可能比维他命水平D更低的人老化缓慢）可知本题答案为D选项．
27题答案：C 考查细节推理，文章主要讲的是太阳光产生的维他命D能够延缓老化，并且在与老化相关的疾病（如心脏病与癌症）方面有保护性作用；虽然太阳光也有可能导致我们皮肤癌的风险，但是很明显其利要大于弊．而且文章也有很多地方强调了太阳光的好处，如倒数第四段This could help to explain how vitamin D has a protective effect on many ageing related diseases，such as heart disease and cancer（这有助于解释维他命D是如何在很多与老化相关的疾病（如心脏病与癌症）方面起到保护性作用的）、倒数第三段Although it might sound absurd（荒唐的），it's possible that the same sunshine which may increase our risk of skin cancer may also have a healthy effect on the general ageing process（尽管听起来荒唐，有可能增加我们皮肤癌风险的太阳光也有可能对于整体的老化过程有健康的作用）以及最后一段Other studies have suggested the vitamin plays a key role in protecting against cancer and heart disease（其他的研究表明维他命在保护预防癌症与心脏病方面起到关键作用），这些都说明太阳光的利要大于弊．注意D选项不是推迟，而是已经给出的文章事实．
28题答案：B 考查文章标题，本文主要讲的是研究表明太阳光产生的维他命D能够延缓衰老，从而使人保持年轻．故本题答案为B选项，其余选项概括都不准确．
点评 本文是一篇健康环保类阅读，题目涉及多道细节理解题，做题时结合原文和题目有针对性找出相关语句进行仔细分析，结合选项选出正确答案．推理判断也是要在抓住关键句子的基础上合理的分析才能得出正确的答案．
