Unit 1 Section Ⅱ Welcome to the unit（配套课件PPT）-【步步高】2025-2026学年高二英语选修第二册学习笔记（译林版·新教材）

该高中英语课件围绕“Covid-19的传播、影响及防控”核心主题，通过速读整体理解文意、细读深度获取细节、读后语法填空的阶梯式设计，构建从文本整体感知到语言细节应用的学习支架，衔接课文理解与语言知识巩固。 其亮点在于融合语言能力与思维品质培养，如长句难句分析中对“only＋状语”倒装结构的句式拆解及仿写，提升学生复杂句式理解与表达能力；阅读理解题通过细节推理、态度推断等题型，锻炼逻辑思维。对学生而言，能系统提升语言运用与思维能力，对教师则提供结构化教学资源，优化课堂效率。

Section Ⅱ Welcome to the unit & Reading Beware and take care Unit 1 Part 1　课文整体理解 Part 2　长句难句分析 Part 3　基础知识达标 训练1 整体理解 课文 3 Step 1　速读——整体理解文意 Ⅰ.明文章大意 What’s the main idea of the text? A.Different kinds of infections. B.The fight against Covid-19. C.The methods to prevent Covid-19. D.More infectious variants of the virus occurring. √ Ⅱ.悉篇章结构 Para.1　　 A.How it spreads. Para.2　　 B.How it evolved. Para.3　　 C.How it affects people. Para.4　　 D.How we protect ourselves. Para.5　　 E.How the world pulled together. Para.6　　 F.Covid-19，a silent and invisible enemy. Para.7　　 G.A call to build a better and more secure future. Step 2　细读——深度获取细节 1.What will happen to a person infected with Covid-19? A.He will suffer a loss of memory. B.His body temperature will become extremely low. C.His immune system will break down. D.He will become tired easily. √ 2.Which word can replace the underlined word in the sentence “Research shows that there are certain settings that allow the virus to spread more easily.” in paragraph 3? A.Conditions. B.Methods. C.Symptoms. D.Regulations. √ 3.Which of the following measures can NOT help control the spread of infectious diseases? A.Wearing a face mask. B.Cleaning hands with soap and water thoroughly. C.Drinking more cold water than usual. D.Receiving vaccines. √ 4.What is the author’s attitude towards our fight against infectious diseases? A.Positive. B.Negative. C.Indifferent. D.Unsatisfied. √ 5.What can we infer from the passage? A.All people show symptoms when they are infected with Covid-19. B.A single country can not prevent the infectious diseases from spreading 　successfully. C.The coronavirus has been the same since the early 2020. D.No vaccine for infectious diseases has been produced so far. √ Step 3　读后——课文语法填空 A new strain of coronavirus 1. (appear) without warning,2.___________(attack) millions of people all over the world.It is a highly infectious disease that can 3. (transmit) easily and swiftly from person 4. person.What is worse，some infected people show no symptoms，so they have no idea 5. they are carriers and spreaders of the virus.6. infectious diseases are frightening，there are also preventive 7. (measure) that everyone can take to help control the spread of them.For example， appeared attacking be transmitted to that Although/Though/While measures maintaining personal hygiene is essential.Cleaning your hands with soap and water thoroughly is necessary 8. (protect) yourself. Receiving vaccines is also essential.In 9. (conclude)，infectious diseases have become a global problem.Only by working together can we march confidently into a better and 10. (secure) future. to protect conclusion more secure 返 回 难句分析 长句 13 1.However，in some cases，the virus causes the body’s own immune system (overreact)，resulting in the body killing its own healthy cells.(P2，Para.2) 句式分析：此句是 句。resulting in...为现在分词短语作 状语，the body killing its own healthy cells为动名词的 。 汉语翻译：_____________________________________________________ _______________________________________________________________ Ⅰ.补句子　析结构 但在某些情况下，病毒会导致人体免疫系统发生过激反应，使得人体杀死自身健康细胞。 to overreact 简单 结果 复合结构 2.This typically happens when people take in respiratory droplets and particles from an (infect) person.(P2，Para.3) 句式分析：此句是 句。主句为“ ”；when引导 从句。 汉语翻译：____________________________________________________ infected 传播一般发生在人吸入感染者的呼吸道飞沫和微粒时。 主从复合 This typically happens 时间状语 3.Research shows that there are certain settings that allow the virus _________(spread) more easily.(P2，Para.3) 句式分析：此句是 句。主句为“ ”；第一个that引导 从句，从句中有there be句型； 第二个that引导_____________从句，修饰settings。 汉语翻译：____________________________________________________ to spread 主从复合 Research shows... 研究表明，某些环境会让病毒更易传播。 宾语 限制性定语 4.What makes this disease even (dangerous) is that infected people who show no symptoms may become unknowing carriers and spreaders of the virus.(P2，Para.3) 句式分析：此句是 句。What引导一个 从句，且在从句中作 ；that引导 从句；who引导 从句，修饰people。 汉语翻译：_____________________________________________________ _______________________________________________________________ more dangerous 主从复合 主语 主语 表语 使这种疾病更加危险的是，无症状感染者无意中可能会成为病毒携带者和传播者。 限制性定语 5.There are preventive measures that everyone can take (help) control the spread of infectious diseases.(P3，Para.6) 句式分析：此句是 句。主句为“_________________________ ___________”；that引导 从句，且在从句中作 语。 汉语翻译：_____________________________________________________ to help 主从复合 宾 　　　　　每个人都可以采取一些预防措施来帮助控制传染病的传播。 There are preventive measures 限制性定语 Ⅱ.研典句　学用法 While humankind has made great progress in the fight against various types of infectious diseases，we still cannot live in a world completely free of them.(P3，Para.6) 尽管人类已经在与各种传染病的斗争中取得了巨大的进步，我们仍然无法生活在一个完全没有传染病的世界。 句式分析：本句为主从复合句。While引导让步状语从句，意为“尽管”。 1　 while的用法 while的用法： • 用作从属连词，意为“虽然，尽管”(常位于句首)，引导让步状语从 句，不与but 连用，但可与yet/still 连用。 • 用作从属连词，意为“当……时”，引导时间状语从句。 • 用作并列连词，意为“而，却”，表示对比(常位于句中)，引导并列 复合句。 (1)(读后续写之场景描写)在救援队用特定的工具来救我的时候，Luca一直在鼓励我。 Luca kept on encouraging me _____________________________________ _____________. (2)我对中国传统画作着迷，而我最好的朋友对中国的饮食充满了热情。 I am keen on traditional Chinese paintings _________________________ ________________________. (3)尽管这些措施并不能永远有效，但它们目前是至关重要的。 _________________________________________，they are vital for now. while the rescue team used specific tools to rescue me while my best friend has a passion for Chinese food While these measures are not effective forever Only by working together，while accepting our individual responsibilities，can we solve both national and global problems.(P3，Para.7) 只有团结协作，人人肩负起各自的责任，我们才能解决国家和全球的问题。 句式分析：本句中“only＋介词短语”放在句首，句子用了部分倒装。while accepting our...为时间状语从句的省略。 2　 “only＋状语”位于句首引起的倒装 “only＋状语”位于句首的倒装有以下三种情况： • “only＋状语从句”位于句首，主句要使用部分倒装 • “only＋介词短语”位于句首，句子要使用部分倒装 • “only＋副词”位于句首，句子要使用部分倒装 注意：(1)部分倒装就是把句中的be动词、助动词或情态动词提到主语之前。 (2)“only＋主语”位于句首时，句子不倒装。 (1)(应用文写作之建议信)只有我们以正确的方式克服大量的困难，我们才能实现我们的梦想。 Only if we overcome large numbers of difficulties in a correct way，___________________________. (2)只有到那时我才意识到勇敢和决心能克服所有的障碍。 Only then _____________________________________________________ ________________________. (3)只有通过强身健体我们才能更好地为建设我们的祖国做出贡献。 _______________________________ can we better make contributions to building our motherland. will we achieve our dreams did I realize that it is bravery and determination that can conquer all the obstacles Only by strengthening our body We need to support each other so that we can march confidently，arm in arm，into a better and more secure future.(P3，Para.7) 我们需要相互支持，以便我们能满怀信心地携手迈向一个更美好、更安全的未来。 句式分析：本句为主从复合句，so that引导目的状语从句。 3　 so that引导目的状语从句 • so that引导目的状语从句，意为“为了；目的是；以便”，相当于in order that，从句中常使用can/could/may/might/will/would/should等 情态动词，从句之前不用逗号。 • so that还可引导结果状语从句，意为“因此；所以”，从句中一般不 用情态动词，从句前常有逗号。 (1)为了我今年能取得更大进步，我每天花费更多的时间学英语。 I spend more time learning English every day _______________________ _____________________________. (2)他经常帮助需要帮助的人，所以我们都把他当作我们的榜样。(人物介绍) He often offers a hand to whoever needs help，______________________ ______________. so that/in order that I can make greater progress this year so that we all take him as our model 课文重点词块默写 1.在一些情况下 _____________ 2.使得某人做某事 _________________ 3.对……造成损害 ________________ 4.吸入 ________ 5.在全球范围内 ________________ 6.对……造成威胁 __________________ 7.为了应对；作为对……的回应 ______________ 8.同……联合，与……合作 ________________ in some cases cause sb to do sth cause damage to take in on a global scale present a threat to in response to join forces with 9.以最快的速度 　______________ 10.昼夜不停地工作 　____________________ 11.各行各业 　______________ 12.进行最大破坏，使尽最坏的招数 　______________ 13.取得进步 　______________ 14.没有……的；不受……影响的 　_______ 15.采取措施做某事 　______________________ 16.保护……以免受 　________________ 17.建立 　_________ 18.暴露于；接触 　______________ 返 回 in record time work round the clock all walks of life do one’s worst make progress free of take measures to do sth protect...from... build up be exposed to 知识达标 基础 30 1.已经流传开来的新型病毒对我们的生活和学习都有很大的影响。 (that引导的定语从句) ______________________________________________________________________________________________________________________________ 2.当我们面对危机的时候，我们学生应该积极响应官方和专家的号召。(when引导的时间状语从句) ______________________________________________________________________________________________________________________________ 单句写作(课文佳句仿写) The novel virus that has made its way has a strong impact on our life and study. When we are faced with the crisis，we students should respond actively to the appeal from authorities and experts. 3.首先，我们应该记住的是，如非必要，我们最好待在家里不要外出。(副词作状语；what引导的主语从句；that引导的表语从句) ____________________________________________________________________________________________________________________________ 4.我们在户外的时候一定要戴口罩，这会减少被感染的风险。(doing作结果状语；mask；infect) ____________________________________________________________________________________________________________________________ Firstly，what we should remember is that we had better stay at home and not go out if not necessary. Do wear masks while we are in the open air，reducing the risk of being infected. 5.只有我们携手合作，我们才能有信心抵抗流行病。(“only＋状语”位于句首引起的倒装) ____________________________________________________________________________________________________________________________ Only by working hand in hand can we have faith in the fight against the pandemic. 组句成篇　以上句子可以加上过渡词语和其他联想内容组成一篇小短文。 ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ The novel virus that has made its way has a strong impact on our life and study.When we are faced with the crisis，we students should respond actively to the appeal from authorities and experts.In order to ease the serious condition，all of students had better do as follows. ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Firstly，what we should remember is that we had better stay at home and not go out if not necessary.Be responsible for ourselves and others.Besides，do wear masks while we are in the open air，reducing the risk of being infected.Washing hands as often as possible is needed，too.Most importantly，everyone ought to have a positive attitude to the campaign against the disease. My dear friends，there may be a long way to go for us.Only by working hand in hand can we have faith in the fight against the pandemic. 返 回 训练1 36 A “Are you all right？” the student asked as she passed me in the hallway.I was in the final stretch of last work before writing my essay.The student，who was 4 years behind me in the same Ph.D.program，went on to say，“I see people from your group working so much，putting in extra hours，even at night.” It set me thinking a lot. Ⅰ.阅读理解 语篇解读　本文为夹叙夹议文。作者通过讲述自己博士生时期的经历，强调要避免过度工作和压力，保持身心健康，提高个人工作效率。 As a first-year Ph.D.student，I was lucky to have kind and understanding advisers.But I felt overwhelming pressure to become a perfect student.I kept finding a million reasons why I was coming into graduate school at a disadvantage compared with my peers.As a student from Colombia，I had been educated at institutions my professors and colleagues had never heard of，I spoke with an accent that was hard to understand，and I was older than most of the people in my cohort. I noticed that most of the people around me seemed to be working all the time.I began to spend many weekday nights and weekends in the lab.But my strategy didn’t work.I crashed from burnout.The tiredness took a toll on my productivity and motivation.During one of many mindless Sundays in the office，I realized I’d fallen into the trap of assuming my colleagues’ work habits were the standard for belonging and being worthy of respect—and it wasn’t sustainable. From then on，I stopped counting the number of work hours I was putting in，leaving space every day for exercising and doing activities that I enjoyed.Eventually，I realized nobody was keeping track of the amount of time I spent in the lab anyway and it wasn’t something I needed to worry about. I noticed that having more time for myself made me more rested and motivated when I went back to work.I continued quietly along this path for years，until that conversation in the hallway.So，when I ran into her again，weeks later，I told her that even though I was feeling a lot of pressure in the final year of my Ph.D.，I was putting my mental and physical health first and wasn’t working overtime.I also began to talk with other students about how quality sleep，physical activity，healthy eating，and reasonable work hours were a daily part of my routine. 1.What can we learn about the student? A.She spent much time in lab work. B.She had finished the Ph.D.program. C.She was concerned about the author. D.She was putting in extra hours at night. √ 推理判断题。根据第一段中这个学生说的话可知，她关注作者的工作情况，询问作者的身体状况，所以是很关心作者。故选C项。 解析 2.How does the author feel about his work at first? A.Anxious. B.Ambitious. C.Dissatisfied. D.Enthusiastic. √ 推理判断题。根据第二段中“As a first-year Ph.D.student，I was lucky to have kind and understanding advisers.But I felt overwhelming pressure to become a perfect student.”可知，作者在刚开始的时候感到压力很大，是很焦虑的。故选A项。 解析 3.Which can replace the underlined phrase “took a toll on” in paragraph 3? A.Added fuel to. B.Had a negative impact on. C.Cast new light on. D.Depended too much on. √ 词义猜测题。根据前文“I crashed from burnout.”以及后文“During one of many mindless Sundays in the office，I realized I’d fallen into the trap...and it wasn’t sustainable.”可知，作者精疲力竭，在办公室工作时毫无头绪，所以疲劳影响了他的工作效率，推知took a toll on是“对……有负面影响”之意。故选B项。 解析 4.What does the author intend to tell us? A.A healthy work-life balance counts. B.A fall into the pit，a gain in your wit. C.Fitting in doesn’t mean working overtime. D.Nothing is difficult to the man who will try. √ 推理判断题。根据最后一段中“So，when I ran into her again，weeks later，I told her...putting my mental and physical health first and wasn’t working overtime...quality sleep，physical activity，healthy eating，and reasonable work hours were a daily part of my routine.”可推知，作者主要想要告诉读者健康的工作与生活的平衡很重要。故选A项。 解析 B Health chiefs are to use artificial intelligence to screen and treat people at risk of hepatitis C(丙型肝炎) under plans to wipe out the life-threatening disease by 2030. 语篇解读　这是一篇新闻报道。文章主要讲述了英国国民医疗服务计划通过用人工智能筛查出患有丙型肝炎的“隐形”患者，为他们提供及时的治疗，以期待在2030年消灭这一病毒。 The National Health Service(NHS) scheme，due to start within weeks in England，aims to identify thousands of patients unaware that they have the virus so that treatment can be given before it is too late. Staff will use AI to comb through patient health records and look for significant risk factors，such as historical blood transfusions(输血) or an HIV diagnosis.Hepatitis C often has no noticeable symptoms until the liver is severely damaged，which means the infected party may not know they are living with a potential killer.It can be cured with modern treatments. Anyone identified by the AI software will be invited for a consultation by their doctors and，if necessary，will experience further screening for hepatitis C.Patients who test positive for the virus—which can be caught from contact with the blood of an infected person，such as by sharing a needle—will be offered antiviral medicines after NHS England struck a deal with three drug companies.Professor Graham Foster，the national clinical chairman for NHS England’s hepatitis C elimination(消灭) programmes，described the scheme as “a significant step forward” in the fight to eliminate the virus. Hepatitis C deaths fell by 35 percent in the five years to 2020，from 482 to 314，according to the latest data from the UK Health Security Agency.The fall in deaths was thanks to earlier detection of the virus and improved access to treatments，health experts said. NHS staff will also visit at-risk communities in specially equipped vans(货车)，to test for the virus and carry out liver health checks，in a bid to wipe out the virus in England before the 2030 goal set by the World Health Organization. 5.What is the purpose of the NHS scheme? A.To make the most of artificial intelligence. B.To record the blood transfusions in the history. C.To diagnose the patients with serious unnoticeable symptoms. D.To pick out the potential patients to provide timely treatments. √ 细节理解题。根据第二段第一句可知，国民医疗服务计划的目的是识别已感染该病毒却不自知的患者，以便给予他们及早地治疗。也就是挑选出潜在患者以提供及时治疗。故选D。 解析 6.What can we infer from paragraph 3? A.NHS scheme can be helpful in removing the hepatitis C virus. B.Hepatitis C can be spread through contact with blood of patients. C.All the patients have to be re-examined again for the hepatitis C. D.Related consulting service will be arranged by the doctor for free. √ 推理判断题。根据第三段中的“Patients who test positive for the virus—which can be caught from contact with the blood of an infected person...”可知，这种病毒可以通过与感染者的血液接触而感染。由此推知，丙型肝炎可通过与患者血液接触传播。故选B。 解析 7.Why did hepatitis C deaths decline in the 5 years to 2020? A.Because the related figure was updated on time. B.Because the liver healthy check-ups were scheduled. C.Because the virus was discovered earlier and better treatments were available. D.Because the virus was tested in advance and communities were well-equipped. √ 细节理解题。根据第四段第二句可知，病毒的早期发现和治疗途径的改善使得死亡人数下降。故选C。 解析 8.What is the main idea of the passage? A.Hepatitis C is a life-threatening disease. B.Hepatitis C deaths in the UK have declined. C.NHS scheme helps to kill the hepatitis C virus. D.AI is a new weapon against deadly hepatitis C. √ 主旨大意题。通读文章内容可知，文章首段提出了核心话题“卫生官员用人工智能筛查和治疗有丙型肝炎的人并计划消灭这种疾病”，且在后文讲述了其取得的成效以及对此项目的期许。由此可知，选项C(国民医疗服务计划有助于消灭丙型肝炎病毒)贴合主题。故选C。 解析 Online debates，conducted on virtual platforms on the Internet，have somehow taken over in being beneficial，as compared to real life debates，for many reasons.For example，they favor more in-depth analysis—This one is especially for the main participants in the debate. Ⅱ.七选五 语篇解读　本文是一篇说明文。文章讲述了在虚拟平台上进行的在线辩论的优点。 They put forward their views from a place where they’re comfortably seated. 1 That is why online debaters can comprehend and think their competitors’ arguments while they write down their own points of view. A.Online debates are much quicker to organize. B.The ability to comment allows people to share their views. C.There is no chance of a point discussed slipping from the mind. D.In other words，the good topics for a debate will never be out of date. E.On an online debating platform，a citizen shares the space with leading thinkers. F.Besides，they have time and means to explore further before sharing their thoughts. G.All that’s needed is a topic and experts who can take out time to write some words on the topic. √ 空前“For example，they favor more in-depth analysis—This one is especially for the main participants in the debate.They put forward their views from a place where they’re comfortably seated.”举例说明在线辩论的优势；F项中的Besides表示递进，与上文是递进关系，进一步列举在线辩论的优势。故选F。 解析 2 You don’t need to find a place or arrange for the audience to be seated. A.Online debates are much quicker to organize. B.The ability to comment allows people to share their views. C.There is no chance of a point discussed slipping from the mind. D.In other words，the good topics for a debate will never be out of date. E.On an online debating platform，a citizen shares the space with leading thinkers. F.Besides，they have time and means to explore further before sharing their thoughts. G.All that’s needed is a topic and experts who can take out time to write some words on the topic. √ 空处为段落主旨句。根据空后内容可知，本段介绍在线辩论更容易组织，不需要找辩论的场所或者安排观众就座等流程，组织起来更快。A选项(在线辩论组织起来要快得多)最适合作本段的主旨句。故选A。 解析 The experts and opinion formers don’t need to take an entire day out from their busy schedules to come to the venue and speak. 3 A.Online debates are much quicker to organize. B.The ability to comment allows people to share their views. C.There is no chance of a point discussed slipping from the mind. D.In other words，the good topics for a debate will never be out of date. E.On an online debating platform，a citizen shares the space with leading thinkers. F.Besides，they have time and means to explore further before sharing their thoughts. G.All that’s needed is a topic and experts who can take out time to write some words on the topic. √ 根据空前“The experts and opinion formers don’t need to take an entire day out from their busy schedules to come to the venue and speak.”可知，在线辩论不需要专家和舆论引导人拿出一整天的时间参加。G选项(一切所需要的只是一个话题和能抽出时间就这个话题写一些评论的专家)符合语境。故选G。 解析 Online debates leave a lasting impression.The debates and the comments on them are archived(存档) by the debate website and anyone who wants to get back to the discussion can do so at any time. 4 This is because it can all be seen again on the website，including every word，every argument. A.Online debates are much quicker to organize. B.The ability to comment allows people to share their views. C.There is no chance of a point discussed slipping from the mind. D.In other words，the good topics for a debate will never be out of date. E.On an online debating platform，a citizen shares the space with leading thinkers. F.Besides，they have time and means to explore further before sharing their thoughts. G.All that’s needed is a topic and experts who can take out time to write some words on the topic. √ 空前“The debates and the comments on them are archived(存档) by the debate website and anyone who wants to get back to the discussion can do so at any time.”介绍了在线辩论内容可存档，可随时回到辩论中；由空后的“This is because”可知，下文解释了空处的原因，可以在网站上再次观看，结合上文在线辩论的内容可以存档可推断，C选项(讨论过的观点是不可能忘记的)符合语境。故选C。 解析 Also，if there are some developments on the issue，then a comment on the issue will tell all the participants to get back to the debate. 5 It’s like keeping the doors open to people who want to learn more and share. A.Online debates are much quicker to organize. B.The ability to comment allows people to share their views. C.There is no chance of a point discussed slipping from the mind. D.In other words，the good topics for a debate will never be out of date. E.On an online debating platform，a citizen shares the space with leading thinkers. F.Besides，they have time and means to explore further before sharing their thoughts. G.All that’s needed is a topic and experts who can take out time to write some words on the topic. √ 空前“Also，if there are some developments on the issue，then a comment on the issue will tell all the participants to get back to the debate.”说明如果辩论有了新的发展，参与者可以随时回到辩论中，D选项(换句话说，适合辩论的好话题永远不会过时)符合语境，对上文进行解释说明，说明在线辩论的话题不会过时，因为随时都可以重新回到话题中。In other words是关键词。故选D。 解析 In 1951，a young mother of five named Henrietta Lacks visited The Johns Hopkins Hospital.Upon 1. (care) examination，the famous doctor Howard Jones discovered a large cervical tumor(宫颈肿瘤). Ⅲ.语法填空 语篇解读　本文是一篇说明文。文章主要介绍了海拉细胞被广泛应用于医学研究，造福全人类。 careful 考查形容词。空处修饰名词examination，应用形容词作定语。故填careful。 解析 A small number of her cancer cells 2. (collect) during a medical test were sent to Dr.George Gey’s nearby lab. collected 考查非谓语动词。分析句子结构可知，空处应用非谓语动词，collect与被修饰词her cancer cells之间为逻辑上的被动关系，应用过去分词形式作后置定语。故填collected。 解析 For years，Dr.Gey，a well-known cancer and virus researcher，had been collecting cells from all patients 3. came to The Johns Hopkins Hospital with cervical cancer， who/that 考查定语从句。分析句子结构可知，空处引导限制性定语从句，修饰先行词patients，指人，关系词在从句中作主语，应用who/that引导。故填who/that。 解析 regardless of 4. (they) race or socioeconomic position，but each cell 5. (rapid) died in Dr.Gey’s lab. their 4.考查代词。修饰名词race or socioeconomic position，应用形容词性物主代词。故填their。 5.考查副词。空处修饰动词died，应用副词形式，作状语。故填rapidly。 解析 rapidly What Dr.Gey soon discovered 6. (be) that Mrs Lacks’ cells were unlike any of the others he had ever seen：where other cells would die，Mrs Lacks’ cells doubled every 20 to 24 hours. was 考查动词的时态和主谓一致。根据上下文可知，句子描述过去的情况，应用一般过去时，且主语为what引导的主语从句，谓语动词应用第三人称单数形式。故填was。 解析 Today，these incredible cells，named “HeLa” cells，are used for 7. (study) the effects of drugs and viruses 8. the growth of cancer cells without experimenting on humans. studying 7.考查非谓语动词。空处位于介词for之后，应用动名词形式，作宾语。故填studying。 8.考查介词。the effects on/upon sth为固定搭配，意为“对某物的影响”，所以空处应用介词on/upon。故填on/upon。 解析 on/upon Scientists use “HeLa” cells to test the effects of radiation(辐射)，to study the human genome，and to learn more about how viruses work. These cells also played 9. important role in the 10. (develop) of the polio vaccine(小儿麻痹症疫苗). an 9.考查冠词。play an important role in为固定搭配，意为“在……中起重要作用”，important发音以元音音素开头，应用不定冠词an。故填an。 10.考查名词。由the和of可知，应用名词development，表示“研发”，作介词in的宾语。故填development。 解析 development 返 回 本课结束 $