一、课文原文及逐段翻译
Unit Nine Lesson 3 Epidemics Explained／流行病探因
第1段原文：An epidemic is the name given to an infectious disease that rapidly spreads to a large number of people within a short period of time—usually two weeks or less. Epidemics have been happening for as long as there have been people living on Earth. They can be caused by several different factors, such as a virus being carried into an area, or changes in the way people live, like more people living in an area, which increases the chances of them coming into contact with a bacteria or virus.
译文：流行病是指在短时间内(通常两周或更短)迅速在大量人群中传播的传染性疾病。自地球上有人类生活以来，流行病就一直存在。它们可能由不同因素引起，例如病毒被带入某个地区，或者由于人们生活方式的改变，比如说某一地区居住的人群增多，从而增加了接触细菌或病毒的几率。
第2段原文：Each disease can only officially be classified as an epidemic once a certain number of deaths have occurred from the disease. The number of deaths is different for every disease. So a very rare disease will have a low baseline and just a few cases of it in one place will be classified as an epidemic; as opposed to more common diseases, such as the flu, that have a higher baseline. The common cold is a widespread virus that affects millions of people, but it is not seen as being a serious enough condition to deserve the classification of epidemic.
译文：只有致死病例达到一定数量，某种疾病才会被正式定性为流行病。每种疾病的死亡数量各不相同。罕见疾病的基线很低，即使某一地区只出现少数病例，也会被认定为是流行病;与此相反，常见疾病的基线较高，如流感。普通感冒由一种广泛传播的病毒引起，可感染数百万人，但它并没严重到可以被称为流行病。
第3段原文：With recent press reports drawing parallels between bird flu and killer epidemics of the past, Jim Smith looks at the sometimes depressing history of epidemics for clues about how we can create a more positive future without epidemics.
译文：最近有新闻报道，吉姆·史密斯将禽流感和过去致命的流行病做对比，在屡屡令人感到沮丧的流行病史中寻找线索，从而创造一个远离流行病的美好未来。
第4段原文：Since bird flu first appeared in 1997, it has taken more than a hundred lives. Many people fear it could be the next global epidemic, especially as scientists who have gone into detail studying tissue samples from the bodies of people who died of the 1918 Spanish Flu have proved that bird flu is a modern adaptation of that virus.
译文：禽流感自1997年首次出现以来，已经夺去了一百多人的生命。科学家们仔细研究了1918年西班牙流感死亡者尸体的组织样本，证明禽流感是该病毒的现代变异版本，许多人担心它可能会引起下一场全球流行病。
第5段原文：One of the earliest epidemics on record happened between about 500 and 550 CE. Scientists now estimate that up to 50% of the area’s population died from the epidemic, making it one of the main causes of the fall of the Roman Empire. Then, in the 1330s, this epidemic returned, this time in Asia. It spread rapidly to Europe and became known as “The Black Death” because one visible symptom was black spots on the body.
译文：人类有记载的最早的流行病，大约发生在公元500年至550年之间。现今科学家估计，发病区域多达50%的人口死于这一流行病，成为罗马帝国衰落的一个主要原因。接着，14世纪30 年代，这一流行病又卷土重来，这次发生在亚洲，并迅速传播到欧洲。由于患者身上会出现明显的黑斑症状，这种流行病被称为“黑死病”。
第6段原文：Centuries later, the Great Flu Epidemic of 1918, also called the Spanish Flu, struck near the end of World War Ⅰ. Families who had only just got through the war now had to bury their loved ones who had died of the disease. As a result of the war, more people were travelling and moving perhaps than ever before in history and this caused the epidemic to spread worldwide. Having killed up to 50 million people in 18 months, the Spanish Flu is believed to have been the most severe epidemic in history. More people died of the flu than died in the war. Initially, many people believed that such epidemics no longer posed a threat until very recently when SARS became a cause for concern.
译文：几个世纪后，第一次世界大战快结束时爆发了1918年大流感，又称西班牙流感。刚刚熬过战争的人们现在不得不埋葬他们死于疾病的亲人。战争引发的人口流动前所未有，从而导致这一流行病蔓延到全世界。西班牙流感在18个月内造成5000万人死亡，成为历史上最严重的流行病。死于该病的人比死于战争的人还要多。最初，人们以为这种大规模流行病不会再对人类构成威胁，直至非典出现，再次让全球陷入担忧。
第7段原文：The SARS epidemic began in 2002 with a case of lung disease in Guangdong Province. It spread to Canada, Vietnam and Singapore and lasted until 2003. SARS was examined by scientists, who were confused by this new disease and wanted to learn more about it and its causes. Infection rates went up steadily, and in the course of the outbreak, about 8,000 people were infected over nine months. Since the end of the SARS epidemic, scientists have been doing trials on treatments to prevent any future outbreaks.
译文：非典疫情始于2002年广东省的一例肺部疾病，后蔓延到加拿大、越南和新加坡，并一直持续到2003年。科学家对这种新型疾病感到困惑，对SARS病毒进行检测，以期了解该病与致病原因的更多信息。非典的感染率不断上升，在爆发期九个月内感染了约8000人。非典疫情结束后，科学家们一直在试验各种治疗手段，以防止未来疫情再爆发。
第8段原文：Then, from 2013 to 2016, there was the most widespread outbreak of the Ebola Virus Disease (EVD) in West Africa, which resulted in a major loss of life in a number of west African countries. 11,310 deaths were officially recorded, but the actual number of deaths is probably much higher. The virus was extremely infectious and the survival rate was as low as 30% in some areas, indicating that very few people got over it.
译文：随后，2013年到2016年间，西非爆发了大规模传染病——埃博拉出血热(EVD)，夺去了这一地区多个国家的很多人的生命。官方统计的死亡人数为11310 人，而实际死亡人数可能要更高。该病毒传染性极强，一些地区的存活率低至30%，也就是说很少有人能康复。
第9段原文：Despite, or perhaps because of, the epidemics the world has faced in recent years, governments worldwide have underlined the fact that they want thorough and systematic medical research on epidemics to get at the causes and come up with cures as soon as possible. Countries will need to work together to do this because teamwork among nations across the globe can save lives.
译文：尽管(或者是因为)近年来全球爆发了流行病，世界各国政府都已经强调，要对流行病进行彻底和系统地医学研究，以便尽快找出原因并找到治疗方法。这需要各个国家的共同努力，因为全球各国之间的团队合作才能拯救生命。
教材录入说明：教材标题印作 Eqidemics Explained，规范拼写为 Epidemics Explained，本文按规范形式讲解；World War Ⅰ 中 Ⅰ 为罗马数字「一」。
二、重点单词
epidemic n. a disease that spreads quickly to many people 流行病；标题 Epidemics Explained。
infectious adj. able to pass from one person to another 传染性的；an infectious disease。
bacterium n. (pl. bacteria) a very small living thing 细菌；课文用复数 bacteria。
virus n. a tiny organism that causes disease 病毒；与 bacteria 并列。
classify v. to put into a particular group 归类、定性；be officially classified as an epidemic。
baseline n. a standard level used for comparison 基线；have a low / higher baseline。
widespread adj. found over a large area 广泛传播的；a widespread virus。
parallel n. a similarity between two things 相似点；draw parallels between A and B。
tissue n. the material forming part of a body （身体）组织；tissue samples 组织样本。
sample n. a small amount taken for testing 样本。
adaptation n. a changed form suited to new conditions 变异体、适应版本；a modern adaptation of that virus。
symptom n. a sign of illness 症状；one visible symptom was black spots。
severe adj. very serious 严重的；the most severe epidemic in history。
initially adv. at first 最初；用于引出「旧看法」，后文常有转折。
pose v. to create a problem or danger 造成、构成；pose a threat 构成威胁。
infection n. the act of being infected 感染；Infection rates went up steadily。
trial n. a test to find out how well something works 试验；do trials on treatments。
outbreak n. a sudden start of a disease 爆发；prevent any future outbreaks。
underline v. to emphasise 强调；have underlined the fact that...。
systematic adj. done in an organised way 系统的；与 thorough 并列。
三、一词多义和熟词生义
draw：熟义 v. 画、拉 → draw parallels between bird flu and killer epidemics of the past 意为「把……与……作类比」。draw a conclusion / draw attention 同属抽象义。
case：熟义 n. 箱子、案例 → 课文义「病例」。just a few cases of it in one place 某地仅出现少数病例；began in 2002 with a case of lung disease 始于 2002 年的一例肺部疾病。
condition：熟义 n. 条件、状况 → 课文义「病症、病情」。not seen as being a serious enough condition to deserve the classification of epidemic 普通感冒没严重到够得上「流行病」的名号。
strike：熟义 v. 击打、罢工 → 课文义（疾病）「侵袭、爆发」。the Great Flu Epidemic of 1918 ... struck near the end of World War I。
take：熟义 v. 拿、花费 → it has taken more than a hundred lives 意为「夺去一百多条生命」；up to 50% of the area's population died 与此同属数据表达。
get over / get at / come up with：三个 get / come 短语易混——very few people got over it 康复；get at the causes 查明原因；come up with cures 找到疗法。
deserve：熟义 v. 值得、应得 → deserve the classification of epidemic 够得上被定性为流行病，宾语是抽象「名分」，不宜译作「值得奖励」。
四、重点词块
【定义与判定】
1. be the name given to 对……的称呼 2. rapidly spread to a large number of people 迅速传播给大量人群 3. within a short period of time 在短时间内 4. be caused by several different factors 由多种因素引起 5. come into contact with a bacteria or virus 接触细菌或病毒 6. be officially classified as 被正式定性为 7. a certain number of deaths 一定数量的死亡 8. have a low / higher baseline 基线低 / 高 9. as opposed to 与……相反 10. deserve the classification of 够得上……的定性
【历史叙述】
1. draw parallels between A and B 把 A 与 B 类比 2. look at the sometimes depressing history of 回望时而令人沮丧的历史 3. one of the earliest epidemics on record 有记载最早的流行病之一 4. up to 50% of the area's population 该区域多达半数人口 5. one of the main causes of the fall of 衰落的主因之一 6. become known as 被称为 7. struck near the end of 在……快结束时爆发 8. get through the war 熬过战争 9. bury their loved ones 埋葬亲人 10. spread worldwide 蔓延全球
【数据与影响】
1. take more than a hundred lives 夺去百余条生命 2. go into detail studying tissue samples 细致研究组织样本 3. die of 死于 4. a modern adaptation of that virus 该病毒的现代变体 5. pose a threat 构成威胁 6. infection rates went up steadily 感染率持续上升 7. in the course of the outbreak 在疫情过程中 8. result in a major loss of life 造成大量死亡 9. be officially recorded 官方记录为 10. as low as 30% 低至 30% 11. indicating that 表明……
【应对与合作】
1. do trials on treatments 进行治疗试验 2. prevent any future outbreaks 防止未来疫情 3. underline the fact that 强调……这一事实 4. thorough and systematic medical research 彻底而系统的医学研究 5. get at the causes 查明原因 6. come up with cures 找到疗法 7. as soon as possible 尽快 8. work together 共同努力 9. teamwork among nations across the globe 全球各国间的合作 10. save lives 拯救生命
【时间衔接】
Since / Then / Centuries later / Initially / until very recently when / Since the end of / Then, from 2013 to 2016 / Despite, or perhaps because of —— 全文靠时间词把四段编年史串成一条线。
五、长难句拆解
句1
【原句】With recent press reports drawing parallels between bird flu and killer epidemics of the past, Jim Smith looks at the sometimes depressing history of epidemics for clues about how we can create a more positive future without epidemics.
【主干】Jim Smith looks at the history of epidemics for clues.
【分层】With + 名词 + 现在分词构成复合结构（recent press reports drawing parallels...），作背景状语；主句为 looks at ... for clues（for 表目的）；about 后接 how 引导的宾语从句，作 clues 的补充说明。
【翻译】近期报道把禽流感与历史上致命的流行病相提并论，在这样的背景下，吉姆·史密斯回望这段时而令人沮丧的流行病史，想从中找到线索，看看我们如何创造一个没有流行病的更好未来。
【考点】with 复合结构（with + n. + doing）+ 介词后接宾语从句；这是说明文常见的「由现实引入历史」过渡句。
句2
【原句】Having killed up to 50 million people in 18 months, the Spanish Flu is believed to have been the most severe epidemic in history.
【主干】The Spanish Flu is believed to have been the most severe epidemic.
【分层】Having killed... 为现在分词完成式作状语，表示该动作先于谓语、且是同一主语主动发出；is believed to have been 为「被动 + 不定式完成式」，说明「被认为是（此前）最严重的」；up to 50 million 与 in 18 months 为数据状语。
【翻译】西班牙流感在 18 个月内夺去多达 5000 万人的生命，被认为是史上最严重的流行病。
【考点】非谓语完成式 Having done 与不定式完成式 to have done 同句出现；be believed / said / reported to have done 是新闻与说明文的高频句型。
句3
【原句】Despite, or perhaps because of, the epidemics the world has faced in recent years, governments worldwide have underlined the fact that they want thorough and systematic medical research on epidemics to get at the causes and come up with cures as soon as possible.
【主干】Governments worldwide have underlined the fact that they want research to get at the causes and come up with cures.
【分层】Despite, or perhaps because of 为插入式并列介词短语，先让后因，写「正是疫情推动了决心」；the epidemics 后为省略关系代词的定语从句 (that) the world has faced；that they want... 为 fact 的同位语从句（that 不作成分）；to get at... and come up with... 为并列不定式作目的状语。
【翻译】尽管——或者也许正因为——近年来世界经历了这些流行病，各国政府都强调：希望对流行病开展彻底而系统的医学研究，以便尽快查明病因、找到疗法。
【考点】插入语 + 省略关系代词的定语从句 + 同位语从句 + 并列不定式目的状语；一句话收束全文并提出行动纲领。
六、语法点清单（从句与非谓语）
一、从句
1. 定语从句：an infectious disease that rapidly spreads...；a virus being carried into an area（现在分词被动式作后置定语）；people who live... 类结构；scientists who have gone into detail studying tissue samples；people who died of the 1918 Spanish Flu；Families who had only just got through the war；which resulted in a major loss of life（非限制性）；the epidemics (that) the world has faced（省略关系代词）。
2. 同位语从句：the fact that they want thorough and systematic medical research（that 不作成分，只说明 fact 内容）。
3. 宾语从句：how we can create a more positive future；have proved that bird flu is a modern adaptation；Many people fear (that) it could be the next global epidemic。
4. 状语从句：Since bird flu first appeared in 1997（since + 过去时，主句用现在完成时）；until very recently when SARS became a cause for concern；especially as scientists ... have proved...（原因）；because teamwork ... can save lives。
二、非谓语
1. 过去分词作定语：the name given to an infectious disease；11,310 deaths were officially recorded；with their faces covered（另课）。
2. 现在分词作定语 / 状语：being carried into an area；like more people living in an area；Having killed up to 50 million people（完成式，先于谓语）；indicating that very few people got over it（结果状语）。
3. with 复合结构：With recent press reports drawing parallels...
4. 不定式：is believed to have been...（完成式）；to get at the causes and come up with cures（并列目的状语）。
三、被动与时态
1. 被动：be classified / be seen as / be examined / be officially recorded / is believed to have been / have been doing trials。
2. 现在完成时：it has taken more than a hundred lives；governments have underlined；scientists have been doing trials（现在完成进行时，强调持续）。
3. 过去完成时：Families who had only just got through the war；与一般过去时的编年叙述配合，区分「更早」与「当时」。
四、数据与程度表达
up to 50% / more than a hundred / up to 50 million / about 8,000 / 11,310 / as low as 30% / more ... than ...（More people died of the flu than died in the war）——说明文用数字与比较级替代形容词，是本篇最鲜明的语言特征。
七、逻辑链
① 下定义：流行病=短时间内（通常两周内）迅速传播给大量人群的传染病；自有人类便存在，成因包括病毒输入、生活方式改变、人口密度上升。
② 给标准：死亡数达标才「正式定性」；基线因病而异——罕见病几例即算，普通感冒感染数百万人却不算，先破除「传染广=流行病」的直觉。
③ 切入视角：媒体把禽流感与历史致命疫情类比，Jim Smith 从「时而令人沮丧」的历史中找线索，目标是创造一个没有流行病的未来。
④ 当代警报：禽流感 1997 年至今夺去百余命；科学家比对 1918 年死者组织样本，证明它是该病毒的现代变体，故很多人担心下一场全球疫情。
⑤ 编年一（古代）：约公元 500–550 年，致死达区域人口半数，成为罗马帝国衰落主因之一；1330 年代在亚洲复燃并传至欧洲，因黑斑症状得名「黑死病」。
⑥ 编年二（1918）：一战尾声爆发大流感，战争带来前所未有的人口流动，使其蔓延全球；18 个月夺 5000 万人，比战争死亡更多，被认为史上最严重。
⑦ 编年三、四（当代）：2002 年 SARS 自广东一例肺病起，九个月感染约 8000 人，此后持续试验疗法；2013–2016 西非埃博拉，官方 11310 死，部分区域存活率低至 30%。
⑧ 结论：尽管——也许正因为——近年疫情，各国强调彻底系统的医学研究，尽快查明病因、找到疗法；且必须跨国合作，因为全球协作才能救命。
写法提炼：定义 → 判定标准 → 现实触发 → 四段编年史（时间 + 数据 + 后果）→ 合作倡议。每段几乎都用「时间状语 + 数字 + 结果状语」三件套，是说明文最稳的段落公式。
八、写作迁移（仿写与输出）
仿写模板（编年式说明文）：X is the name given to ... Only once ... can it officially be classified as ... Since ..., it has ... One of the earliest ... happened between ... Centuries later, ... Then, from ... to ..., ... Despite, or perhaps because of ..., ... have underlined the fact that ...
示范（以「校园阅读推广」为题）：A reading campaign is the name given to a school-wide effort to make books part of daily life. Only once reading time is fixed in the timetable can it be classified as a real programme. Since 2019, our school has added twenty minutes of silent reading every morning. Then, from 2022 to 2024, the library recorded over 30,000 loans. Despite, or perhaps because of, the exam pressure, teachers have underlined the fact that steady reading improves writing far more than extra drills.
可迁移句式：① Having done ... , ... is believed to have done ...（完成式 + 被动）② the fact that ...（同位语从句）③ With + n. + doing（背景状语）④ indicating that ...（结果状语）⑤ since + 过去时，主句用现在完成时 ⑥ up to / as low as / more ... than ...（数据表达）。
输出任务：以「从历史看公共卫生」为题写 120 词短文。要求：用 1 个现在分词完成式作状语、1 个同位语从句、1 个 since + 现在完成时、1 个 be believed to have done；至少调用 2 个本课数据型词块（up to / as low as / in the course of / pose a threat / come up with cures），并仿照课文用 3 个时间词串起三个事实。
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