题目

题型：不详难度：来源：

A.  Weather is to blame B.  Divided opinions C.  Inheriting（遗传） characteristics D.  Home of the redheads E.  Greater sensitivity to pain F.  Gene mutation（基因变异）

 
小题1:
Britain may be the most red-headed country in the world. About 1 to 2 percent of the world’s population has red hair, but in the UK the numbers are much higher, with 13 percent of Scots, 10 percent of the Irish, and 6 percent of people in England having red hair, according to the BBC.
小题2: 
Scientists have tried to explain why some people have red hair for some time and now they may have found an answer: the dull weather in Britain. The human body needs vitamin D from sunshine, but unfortunately people living in Britain do not have enough of it because of its maritime climate. In fact, Britain gets even more cloud than countries in the far north of Europe. In Sweden, for example, the average daily hours of sunshine is 5.4 . In Scotland it is only 3.1 hours.
小题3:
To deal with this, the DNA of people living in these areas has changed slightly; scientists call this a mutation. Originally, the coloring on our body is a mixture of two kinds of melanin – black melanin is suppressed while only red / yellow melanin is made. The result is red hair, light skin color, freckles and a greater sensitivity to sunlight.
小题4:
However, what’ s more interesting is that the redhead DNA mutation is recessive, which means it is hidden and can often skip generations without showing. At least 1.6 million Scots carry a redhead gene mutation, and most are unaware that they do. This is why a person who does not have red hair can still produce red-haired children if he or she is a carrier of this special DNA.
小题5:
The research on red hair, like many areas of science, is contradictory(不一致). In 2002 researchers showed that redheads are more sensitive to pain, and need more anesthetic during surgery than people with blonde or dark hair. However, in 2005 scientists found that a MCRIR mutation gives redheads a higher tolerance for pain. Research into these aspects of red hair genetics continues. Redheads should though be more careful about their exposure to sunlight as they are at an increased risk of contracting skin cancer. If you are a redhead, the advice is not to stay out of the sun, but to be careful about how much exposure you get, and to cover yourself with a high factor sunscreen.

答案

小题1:D
小题2:A
小题3:F
小题4:C
小题5:B

解析

试题分析：本文叙述了英国人有红头发的人占的比例较大，有些人认为主要是由于气候的影响，人们不能吸收足够的维生素D，二是由于基因突变。三是由于遗传的因素。最后一段叙述了科学家的对于红头发的不同的意见。
小题1:根据Britain may be the most red-headed country in the world.英国红头发的人最多，故选D。
小题2:根据the dull weather in Britain.因为天气的原因所以红头发的人多，故选A。
小题3:根据scientists call this a mutation.主要因为基因突变，故选F。
小题4:根据what’ s more interesting is that the redhead DNA mutation is recessive, which means it is hidden and can often skip generations without showing.因为遗传的特征，故选C。
小题5:根据The research on red hair, like many areas of science, is contradictory(不一致).科学家的不同的看法，故选B。
点评：文章由若干段话组成，要求给每段话归纳段落大意，意即找出该段的中心思想、主旨。读每段话时，要抓住该段话的主题句和核心词汇，正确答案常常是主题句的改写。读每段话时，并不是该段话全要仔细阅读。这样，既浪费时间，也不容易抓住重点。应该抓住该段话的主题句。