第十二篇 The Enemy Within
Allergy has become more and more common over the last 30 years. Now one-third of us are affected by allergy at some point in our lives and half of these sufferers are children. In the UK, three million people suffer from asthma, and five per cent of children suffer from food allergy.
Allergy is a reaction that occurs when the immune system has a strange and unnecessary reaction to a substance which is normally harmless, such as pollen or peanuts. ____1____ To defend your body against an attacker, the immune system remembers these dangerous micro-organisms and attacks them if it meets them again. This work is done by antibodies. The immune system in allergy sufferers makes antibodies against harmless substances, because it mistakenly believes them to be dangerous.
An allergic reaction may not happen the first time a sufferer meets an allergen (the substance causing the reaction, such as pollen, milk or strawberries). Sometimes people can eat nuts for years and then suddenly become allergic to them. What has happened is that the immune system has now decided the substance is dangerous and has made an allergy antibody. This antibody then attaches itself to cells, which contain histamine. ____2____ As they do that, the surface of the cells is broken, and histamine is released. The histamine and other chemicals inflame the tissues. This leads to the symptoms of allergy, such as swelling, rashes, sneezing, sore eyes and breathlessness. Anaphylaxis is the most severe allergic reaction of all and is most often triggered by wasp or bee stings or peanuts. This must be treated immediately.
____3____ Some people are born with the ability to make lots of allergy antibodies, and they are more likely to develop allergies and allergic disorders such as hay fever and asthma.
____4____ We eat more processed foods, with a wide range of additives and colourings; more and more people have central heating and double glazing, making our houses warmer and less draughty-an ideal environment to breed the house dust mite.
There may also be a link between allergies and antibiotics. At one time our immune systems were kept busy fighting off disease and trying to win the battle for health, but antibiotics have reduced the amount of work our immune systems have to do. Now experts think they may direct spare energy to harmless substances such as strawberries. ____5____
A good deal of research is being devoted to finding a cure for allergies. Sufferers may be given medicine to control symptoms, and they may also be offered tests to find out what substances trigger an allergic reaction so that they can avoid contact with these in future.
词汇：
allergy n. 过敏，过敏症
sufferer n. 患者，受害者
asthma n. 哮喘
substance n. 物质
pollen n. 花粉
micro-organism n. 微生物
antibodies n. antibody的复数形式，意为抗体
allergen n. 过敏源
nut n. 坚果
histamine n. 组织胺，组胺
tissue n. 人体组织
symptom n. 病症，征兆
rash n. 疱疹
sneezing n. 打喷嚏
breathlessness n. 呼吸急促，气喘吁吁
anaphylaxis n. 全身性过敏反应，过敏反应
wasp n. 黄蜂
sting n. 蟄，咬
hayfever n. 枯草热，花粉病
additives n. 添加剂，食品添加剂
cure n. 治疗，解药
注释：
1.suffer from...忍受^的折磨
2.be devoted to sth. ...全身心投入于^
练习：
A The immune system is there to protect the body against outside attackers, including viruses, bacteria and parasites.
B In other words our immune systems have become over-sensitive.
C Allergies run in families.
D International differences have been associated with the number of individuals within a population have allergy.
E When the antibodies meet the allergen the next time, they attempt to destroy it.
F Experts believe more people have developed allergies because of changes in our lifestyle which have exposed us to more allergens.
答案与题解：
1.A 该是对机体免疫系统功能的介绍，而文中对免疫系统的首次提及是在该选项的上一句话，即描述过敏反应是免疫系统的活动，该选项故而可被视为是对上一句话的补充与说明。
2.E 本题做题线索有两点，首先是上下文，本段前几句都是对抗体的描述与介绍，故与选项E主题相符，同时第二个做题点为逻辑顺序词，本段的第一句话中提到了An allergic reaction may not happen the first time a sufferer meets an allergen，而该选项中又有了the next time，这两个逻辑顺序词也构成了解题线索。
3.C 该选项在文章的第四段，讲的是过敏反应在特殊人群中的反应，选项C的意思为“过敏反应是具有遗传性的”，与该段后一句some people are born with the ability...相对应。
4.F 文章第五段主要讲的是能导致过敏反应的两个例子，缺少中心句，而选项C恰好能对这两个例子进行概括说明，故答案为选项C。
5.B 该选项为概括总结项，是对前文说的内容进行总结，该段的前面部分提及的是抗生素与过敏反应之间的关系，即其对于人体免疫系统的影响，而该选项则是一个结果性的描述，即免疫系统变得过于敏感了，其可对前文中抗生素的作用进行总结说明。
