Passage 7The Importance of Vaccination1 Measles, which once killed 450 children each year and disabled even more, was nearlywiped out in the United States 14 years ago by the universal use of the MMR vaccine. 2 Butthe disease is making a comeback, caused by a growing anti-vaccine movement andmisinformation that is spreading quickly. 3 Already this year, 115 measles cases have beenreported in the USA, compared with 189 for all of last year.4 The numbers might sound small, but they are the leading edge of a dangerous trend.5 When vaccination rates are very high, as they still are in the nation as a whole, everyone is protected. 6This is called “herd immunity”, which protects the people who get hurt easily, including those who can’t be vaccin ated for medical reasons, babies too young to get vaccinated and people on whom the vaccine doesn’t work.7 But herd immunity works only when nearly the whole herd joins in. 8 When some refuse vaccination and seek a free ride, immunity breaks down and everyone is in even bigger danger.9 That’s exactly what is happening in small neighborhoods around the country from Orange County, California, where 22 measles cases were reported this month, to Brooklyn, N.Y., where a 17-year-old caused an outbreak last year.10 The resistance to vaccine has continued for decades, and it is driven by a real but very small risk. 11 Those who refuse to take that risk selfishly make others suffer.12 Making things worse are state laws that make it too easy to opt out of what are supposed to be required vaccines for all children entering kindergarten. 13 Seventeen states allow parents to get an exemption, sometimes just by signing a paper saying they personally object to a vaccine.14 Now, several states are moving to tighten laws by adding new regulations for opting out. 15 But no one does enough to limit exemptions.16 Parents ought to be able to opt out only for limited medical or religious reasons. 17 But personal opinions? Not good enough.18 Everyone enjoys the life-saving benefits vaccines provide, but they’ll exist only as long as everyone shares in the risks.一．单词和短语Words and expressions* measles /ˈmiːzlz/ n. <医>麻疹;* vaccine /ˈvæksiːn/ n. 疫苗make a comeback 卷土重来* anti-vaccine movement 反疫苗运动misinformation /ˌmɪsɪnfəˈmeʃn/ n. 错误信息* the leading edge 前缘；领先地位* herd immunity /hɜːd/ /ɪˈmjuːnɪtɪ/群体免疫a free ride免费搭车；占便宜；坐享其成selfishly /ˈselfɪʃlɪ/ adv.自私地；* opt /ɒpt/ vi. 选择* opt out 决定退出* exemption /ɪɡˈzempʃn/ n.免除二．参考译文Translation1通过广泛接种麻疹疫苗，麻疹于14年前几乎在美国绝迹（麻疹曾经致使每年平均有450名儿童丧命，更多的人残疾）。
2但由于越来越多的反疫苗运动和错误信息的迅速传播，这种疾病正在卷土重来。
3在美国，今年已有115例麻疹病例报告，而去年全年则为189例。
4这数字听起来可能很小，但它们已经是危险趋势的警戒线了。
5当疫苗接种率非常高时（如今这个国家的接种率总体上说仍然还算高的），每个人都受到保护。
6这被称为“群体免疫力”。
“群体免疫力”可以保护容易得病的人群，包括那些因医疗原因无法接种疫苗的人、年龄太小而无法接种疫苗的婴儿以及疫苗接种无效者。
7但是群体免疫力只有在几乎整个群体都加入时才有效。
8当其中一些人拒绝接种疫苗并企图坐享其成时，群体免疫力就会瓦解，每个人都陷入更高的风险中。
9这种情况正发生于全国各地的一些小型社区——比如，加州奥兰治县本月报告了22例麻疹；去年在布鲁克林的N.Y.,一个17岁孩子发病，引起了疾病的爆发。
10对疫苗的抵制持续了数十年。
这种抵制源于真实存在的但却非常小的接种风险。
11那些拒绝承担风险的人很自私地让别人遭了殃。
12更糟糕的是，一些州的法律使得人们有很大的自由可以选择不让那些上幼儿园的孩子接种本应该必须接种的疫苗。
13有17个州给予家长豁免权，有时只需要签署一份文件表明他们个人反对接种某种疫苗就可以了。
14现在，有几个州正在通过增加新的“退出”条件来加强法律制约。
15但没有一个州采取了充分的措施来限制豁免权。
16父母应该只能出于有限的医疗或宗教原因选择不接种。
17但个人意见呢？可不是个好理由。
18每个人都享受疫苗可以救命的好处，但只有每个人都分担风险，这好处才能实现。
三．理解Comprehension1．The first two paragraphs suggest that ____________.A．a small number of measles cases can start a dangerous trendB．the outbreak of measles attracts the public attentionC．anti-vaccine movement has its medical reasonsD．information about measles spreads quickly2．Herd immunity works well when ____________.A．exemptions are allowedB．several vaccines are used togetherC．the whole neighborhood is involved inD．new regulations are added to the state laws3．What is the main reason for the comeback of measles?A．The overuse of vaccine. B．The lack of medical care.C．The features of measles itself. D．The vaccine opt-outs of some people.四．阅读理解难点Difficulties in comprehension7 But herd immunity works only when nearly the whole herd joins in. 8 When some refuse vaccination and seeka free ride, immunity breaks down and everyone is in even bigger danger.根据上下文，这两句话中“some refuse vaccination and seek a free ride”的隐含之意是“有些人拒绝接种疫苗，并享受着这个群体中别人接种疫苗带来的好处——没有接种疫苗的人患病的风险因身边的人们接种了疫苗而降低。
According to the context, the implication of “some refuse vaccination and seek a free ride” is that some refuse vaccination and enjoy the benefits brought about by others’ vaccination——the risk for those unvaccinated reduced for the vaccination of people around them.五．用另一个单词或短语替换以下摘自本文的单词或短语。