全国通用版 2019版高考英语大一轮复习单元检测卷29Unit4Globalwarming新人教版选修
Unit 4 Global warmingⅠ.阅读理解AThey may be tiny, and live for just three months, but ants could be the key to solving climate change.Rough harvester ants have been found to “weather” minerals in sand to produce calcium carbonate, also known as limestone(石灰岩)．When the ants make this limestone, the process traps carbon dioxide in the rock, ultimately removing it from the atmosphere.It is uncertain how the minerals are changed, however, and theories vary a lot from ants licking the sand to excreting (排泄) the substance.Professor Dorn buried sand at six sites in the Catalina Mountains in Arizona, and Polo Duro Canyon in Texas, 25 years ago. Every five years, he measured the minerals in the sand, and discovered the ants broke down minerals up to 300 times faster than sand left undisturbed.Professor Dorn believes the ants collect calcium and magnesium(镁) and use these elements to make the limestone. This may occur when ants lick sand grains to stick them to the walls of their nests. Alternatively, the limestone could be created from bacteria in the insects gut before it is excreted. This process is similar to what's known as carbon sequestration(隔离)．Natural carbon sequestration is the process on Earth that manages the carbon dioxide expelled by animals and humans. Trees and the oceans help trap this carbon dioxide.Another method is geological sequestration where the carbon dioxide is pumped into underground chamber, or into areas full of calcium and magnesium. Carbon dioxide reacts with these elements to form limestone. It is this latter method that Dorn believes the ants perform naturally.But Professor Dorn claims it is still unknown how much atmospheric carbon is removed by the ants.语篇导读本文为说明文。
多恩教授认为，蚂蚁也许是应对气候变化的关键因素。
他通过实验证明蚂蚁能够吸收空气中的二氧化碳，但是具体能吸收多少至今尚未确定。
1．The fifth paragraph is mainly about ________.A．how ants break down limestoneB．how ants change minerals into limestoneC．how ants decorate their nests with sandD．how ants use sand to kill bacteria解析B主旨大意题。
本段大意：多恩教授认为蚂蚁舔沙砾把它们粘在巢穴的墙上时，可能会收集钙和镁制造石灰岩。
或者，石灰岩可以从蚂蚁的肠道细菌中产生，再排泄出来。
这都是关于蚂蚁如何制造或产生石灰岩的，故选B 项。
2．What is the possible meaning of the underlined word “expelled”？A．Sent out. B．Taken in.C．Broken up. D．Given away.解析A词义猜测题。
本句句意：地球上自然碳汇是处理动物和人类expelled的二氧化碳的过程。
根据常识可知，动物和人类排放二氧化碳。
send out放出；take in 吸收；break up打碎，结束；give away泄露(消息、秘密等)，故选A项。
3．According to Dorn, scientists still don't know ________.A．the effect of CO2 on ants' survivalB．the method of ants' removing CO2C．the amount of CO2 removed by antsD．the time when ants absorb CO2解析C细节理解题。
根据最后一段可知，多恩教授目前尚不清楚蚂蚁吸收了多少大气中的碳，故选C项。
4．The main idea of the passage is that ________.A．ants build their nests to keep CO2 outB．ants use limestone to absorb a great deal of CO2C．ants are pioneers in solving global warmingD．ants may remove CO2 from atmosphere解析D主旨大意题。
第一段说．..but ants could be the key to solving climate change，后面介绍了多恩教授的实验，最后多恩教授称目前尚不清楚蚂蚁吸收了多少大气中的碳。
因此全文主要讲蚂蚁可能会吸收大气中的二氧化碳并介绍相关实验，故选D项。
BDuring a research experiment a marine(海洋) biologist placed a shark into a large holding tank and then released several small fish into the tank. 5.________ The marine biologist then inserted a strong piece of clear fiberglass(纤维玻璃) into the tank, creating two separate parts. She then put the shark on one side of the fiberglass and a new set of small fish on the other.Again, the shark quickly attacked. This time, however, the shark hit the fiberglass divider and bounced off. 6.________ Meanwhile, the small fish swam aroundunharmed in the second part. Eventually, about an hour into the experiment, the shark gave up.This experiment was repeated several dozen times over the next few weeks.7.________ Eventually the shark got tired of hitting the fiberglass divider and simply stopped attacking altogether.The marine biologist then removed the fiberglass divider, but the shark didn't attack. 8.________ So, they swam wherever they wished, free from harm.Like the shark in the story, many of us, after experiencing setbacks and failures, emotionally give up and stop trying. 9.________ In other words, we continue to see a barrier in our heads, even when no “real” barrier exists between where we are and where we want to go.A．At the same time, the shark tried again and again.B．We believe that because we were unsuccessful in the past, we will always be unsuccessful.C．The shark was trained to believe a barrier existed between it and the small fish.D．It kept repeating this behavior every few minutes fruitlessly.E．We should keep on trying even if we meet obstacles.F．Each time, the shark got less aggressive and made fewer attempts to attack the small fish.G．As you would expect, the shark quickly swam around the tank, attacked and ate the smaller fish.语篇导读本文为议论文。
[推荐学习](全国卷)2019届高考英语一轮复习 Unit 4 Global warming课时作业
2019届高考英语一轮复习 Unit 4 Global warming课时作业](https://360docs-1393072327.cos.ap-beijing.myqcloud.com/44ff7a0ba5e9856a561260e9.webp)
Unit 4 Global warmingⅠ.阅读理解ADear Alcohol，You've been around forever. I can remember all the pain you've caused me.Do you remember the night when you almost took my father's life? I do. He loves you. Sometimes I think he loves you more than he loves me. He's addicted to you and to the way you promise to rid him of his problems only to cause more of them. You just sat back and laughed as his car went turning through the street, crashing into two other cars. He wasn't the only one badly hurt by you that night.Do you remember the night of my first high school party? My friends were intrigued by you. They treated you as if they were never going to see you again, drinking all of you that they could. I s pent two hours that night helping my friends who had fallen head over heels for you. “I'm so embarrassed，” they said as I held their hair back so that they could throw up. “I'm sorry，” they said when I called taxis for them, walking them out and paying the driver in advance. “This won't happen again，” they said as they were sent to the hospital to have their stomachs pumped. Two 15yearold girls slept in hospital beds that night due to you.Do you remember the night when you took advantage of my 17yearold neighbor who had to drive to pick up his sister from her dance lesso ns? Do you know how we all felt when he hit another car headon and killed two people in the other car? He died the next morning too. His sister walked home from her dance lesson, and passed police cars and a crowd of people gathering on the s idewalk just two blocks away from the dance studio. She didn't realize her brother was among them at all. She never saw him again. And it was all your fault.I wish you'd walk out of my life forever. I don't want anything to do with you. Look at all the pain you've caused. Sure, you've made people happy too from time to time. But the damage you've caused in the lives of millions is not excusable. Stop attracting the people I love! Stop hurting me, please.Sincerely，Me [语篇解读] 这篇文章是一封书信。
(全国卷)2019届高考英语一轮复习 Unit 4 Body language课时作业 新人教版必修4
Unit 4 Body languageⅠ.阅读理解ARecently，I had lunch with a young Chinese student who studies at a college in New York.He is very bright and aspiring and I enjoyed our conversation.Still I felt frustrated and useless afterwards because I was not able to provide him with any good news.Graduating at the end of this year，he asked me how he could find a job in this country and fulfill his career dreams.In recent years，students who found a job here after graduation have had to go through a cruel lottery system to obtain their HIB working visa.And the success rates have been declining year after year because of the ever growing number of st year，there were 233,000 applicants, and only 30 percent of them were lucky，less than half of the rate in 2013.And it can only become President Donald Trump's immigration policies in this country are tightening up and this trend will continue for at least the next few years.In this case，foreign students studying social sciences，a field in which starting salaries are rarely above the required amount，can kiss their visa hopes goodbye.Compared to the older generation of Chinese students，today's young people no longer consider the US as the only option.Many start to think China offers better opportunities in the longer term.This is not to say that Chinese students in the US are not interested in job opportunities here any more.A few years of work experience in the US can give them leverage when they finally land back in their home country.But if the job opportunities are largely reduced by the tightening of immigration policy，I expect there will be a decline.And if that happens，it is the American economy that will suffer from the loss of those educated，hardworking and talented immigrants.[语篇解读] 本文为一篇记叙文。
2021-2022年高三英语一轮复习题组层级快练29Unit4Globalwarming新人教版选修
2021年高三英语一轮复习题组层级快练29Unit4Globalwarming新人教版选修(I)Ⅰ.阅读理解阅读下列短文，从每题所给的四个选项(A、B、C和D)中选出最佳选项。
(原创)Suffering from malnutrition(营养不良), Regelyn often felt tired and sometimes didn’t want to attend school. Some classmates even laughed at her because of her extremely thin frame.With a limited ine selling boiled corn, Regelyn’s parents had difficulty providing food for her and her four sisters and brothers. Thanks to the healthy meals she received through the nutrition program, Regelyn returned to a normal weight.When she was 10 years old, she graduated from the Children International nutrition improvement program. “I feel very happy because now I am strong ...”reports a nowhealthy teenaged Regelyn.Regelyn’s mother, Arlenda, received nutrition education on planning a balanced diet and cooking simple but nutritious meals. While the family may still struggle to afford decent(相当好的)food, Arlenda hopes she can better use the family’s ine to provide enough healthy food. “We are not asking for delicious meals every day, but just nutritious food enough to feed all seven of us three times a day，” Arlenda explained.Regelyn and her family are not alone. Around the world, countless familiescontinue to feel the pain of hunger. Regular financial contributions to Children International help offer money to important programs that give children like Regelyn chances to have the basic essentials of life — essentials they might never have if there are no such programs.1. Regelyn used to be tired because ________．A. she had to work to support her familyB. she was seriously illC. she was weak because of malnutritionD. she didn’t want to go to school2. From the passage we can know “essentials” probably means ________．A. necessary thingsB. interesting thingsC. unimportant thingsD. useful things3. From paragraph four we can learn that ________．A. Arlenda received education on how to cookB. it is not easy for Regelyn’s parents to provide the whole family with nutritious foodC. Arlenda can cook delicious food for the family every dayD. with the help of the program, Regelyn’s family has bee very rich4. The best title of the passage may be ________．A. Nutrition for a Brighter FutureB. Children InternationalC. Regelyn’s FamilyD. Delicious Food Every Day答案与解析【文章大意】Regelyn是一个因家庭贫穷而营养不良的孩子，在儿童国际营养项目的帮助下身体得以恢复，世界上还有很多被饥饿所困的家庭，本文呼吁人们通过儿童国际给这些家庭提供帮助。
【推荐】全国卷2019届高考英语一轮复习Unit4Globalwarming课时作业新人教版选修.doc
Word文档，精心制作，可任意编辑Unit 4 Global warmingⅠ.阅读理解ADear Alcohol，You've been around forever. I can remember all the pain you've caused me.Do you remember the night when you almost took my father's life? I do. He loves you. Sometimes I think he loves you more than he loves me. He's addicted to you and to the way you promise to rid him of his problems only to cause more of them. You just sat back and laughed as his car went turning through the street, crashing into two other cars. He wasn't the only one badly hurt by you that night.Do you remember the night of my first high school party? My friends were intrigued by you. They treated you as if they were never going to see you again, drinking all of you that they could. I s pent two hours that night helping my friends who had fallen head over heels for you. “I'm so embarrassed，” they said as I held their hair back so that they could throw up. “I'm sorry，” they said when I called taxis for them, walking them out and paying the driver in advance. “This won't happen again，” they said as they were sent to the hospital to have their stomachs pumped. Two 15yearold girls slept in hospital beds that night due to you.Do you remember the night when you took advantage of my 17yearold neighbor who had to drive to pick up his sister from her dance lesso ns? Do you know how we all felt when he hit another car headon and killed two people in the other car? He died the next morning too. His sister walked home from her dance lesson, and passed police cars and a crowd of people gathering on the s idewalk just two blocks away from the dance studio. She didn't realize her brother was among them at all. She never saw him again. And it was all your fault.I wish you'd walk out of my life forever. I don't want anything to do withyou. Look at all the pain you've caused. Sure, you've made people happy too from time to time. But the damage you've caused in the lives of millions is not excusable. Stop attracting the people I love! Stop hurting me, please.Sincerely，Me [语篇解读] 这篇文章是一封书信。
2019届高三英语一轮复习题组层级快练29Unit4Globalwarming新人教版选修62018
题组层级快练29 Unit 4 Global warmingⅠ. 阅读理解There's no better way to experience Santa Monica than on the beach. Learn to ride the waves on the Santa Monica Beach! Surf lessons with professional, expert instructors equal an unforgettable adventure in California.Highlights (最精彩的部分)Enjoy a day away from the noise of the cityClose contact with friendly dolphinsSee native wildlife in their natural environmentInformative, friendly and professional guidePerfect introductions for first－time visitorsAll necessary equipment includedSchedule DetailsYou may schedule surf lesson times from 6 am to 6pm every day all year round, with a duration of 1.5 hours. You will meet your instructors at Lifeguard Tower 28 on the Santa Monica Beach. Instructors are equipped to teach beginning, intermediate and advanced levels, and all children over 4 years of age are encouraged to participate. Your instructors also encourage siblings, friends, couples and families to attend together. Please contact the surf instructor after booking to confirm the specific lesson time.PriceAdult (Age 18－84)Child(Age 4－12)Youth(Age 13－17)Price per person USD 155.00 USD 105.00 USD 125.00If you cancel at least 7 days in advance of the scheduled departure, there is no cancellation fee.If you cancel between 3 and 6 days in advance of the scheduled departure, there is a 50 percent cancellation fee.If you cancel within 2 days of the scheduled departure, there is a 100 percent cancellation fee.1. What can we learn about the surf lesson?A. It is designed for beginners.B. It needs reserving in advance.C. It inspires all children to participate.D. It charges extra money for equipment.2. How much will the Smiths pay if they want to learn to surf with their 4－year －old daughter?A. $ 385B. $ 405C. $ 415D. $ 4353. What's the purpose of this passage?A. To attract people to Santa Monica Beach.B. To introduce Santa Monica Beach surf lessons.C. To review an unforgettable adventure.D. To give people guidance on surfing.答案与解析【文章大意】本文为应用文，介绍了Santa Monica Beach的冲浪课程的相关内容。
高考英语大一轮复习课时达标29Unit4Globalwarming含解析新人教版选修6
课时达标(二十九) Unit 4 Global warming(见学用课时P67)Ⅰ 阅读理解Abicycle. Nothing unusual about that? But at this Bamboo Bicycle Club session, the bikes are being made with bamboo.In all the excitement to claim bicycles the answer to crowded roads, polluted city air and our own health, the materials used to manufacture those bikes often get overlooked. Carbon fiber, for example, is increasingly popular for new bicycles, particularly racing bikes. The material, though lightweight and strong, is difficult to recycle and cannot be melted down and reused in its original form, unlike aluminum and steel. Carbon fiber is also dangerous and dirty to work with, so it's an unlikely material for encouraging people to build and repair their own bicycles. It's also incredibly wasteful. Most people replace a racing bike every three years, adding to carbon fiber waste.Motivated to cut the waste and make bik ebuilding more popular, Marr has set up a club to teach people how to make their own bikes out of bamboo. Far from just panda food, bamboo is a strong and popular building material in Asia, and it's well suited to being shaped into a bicycle frame. It can grow from seed to harvest in less than four years. Still, its sustainability relies on production standards, for example, avoiding the use of chemical fertilizers or pesticides, and ensuring natural forest is not cleared for plantations.The club's worksh op in London makes around 500 bicycles a year, with a twoday session building your own bamboo bicycle costing around ￡600. The club has opened franchises(特许经营权) in Germany and Italy, with more in Canada and South Africa opening soon. As well as teaching people to build bikes, the club was invited by two NGOs working in Kenya last year to help teach students in Malaa near Nairobi how to repair, maintain and build bicycles. The final ambition is to help reconnectpeople with bikes and the materials used to build them.In a recent interview, Marr talked about the trendy bikesharing. “While bikesharing companies have promised lots in terms of more sustainable transport, they haven't yet changed wasteful consumer attitudes，” Marr commented, adding that he was shocked by photos of thousands of unwanted bicycles abandoned in cities across China.语篇导读本文主要介绍的是一个自行车俱乐部为了环保教人们用竹子做自行车。
2021年高考英语调研大一轮复习课时作业29Unit4GlobalwarmingA卷
课时作业29 Global warmingⅠ.课标单词阅读词汇———明其义1．random adj. 胡乱的；任意的2．subscribe vi. 同意；捐赠；订阅vt. 签署(文件)；捐助3．fuel n. 燃料4．data n. 资料；数据5．trend n. 趋势；倾向；走向6．catastrophe n. 大灾难；浩劫7．flood n. 洪水；水灾8．outer adj. 外部的；外面的9．electrical adj. 电的；与电有关的10．casual adj. 随便的；漫不经心的；偶然的11．motor n. 发动机12．can n. 容器；罐头13．microwave n. 微波炉；微波14．nuclear adj. 核的；核能的；原子核的写作词汇———悉其用1．tend vi. 趋向；易于；照顾vt. 照顾；护理2．quantity n. 量；数量3．glance vi. 看一下；扫视n. 一瞥4．advocate vt. 拥护；提倡；主张5．mild adj. 温和的；温柔的；淡的6．range n. 种类；范围7．tendency n. 倾向；趋势8．widespread adj. 分布广的；普遍的9．average adj. 平均的10．pollution n. 污染；弄脏11．circumstance n. 环境；情况12．refresh vt. 使恢复；使振作拓展词汇—————————通其变1．phenomenon n. 现象→phenomena pl现象2．oppose vt. 反对；反抗；与(某人)较量→opposed adj. 反对的；对立的3．consequence n. 结果；后果；影响→consequently adv. 因此；所以4．state vt. 陈述；说明→statement n. 声明；陈述；表达5．steady adj. 平稳的；持续的；稳固的→steadily adv. 平稳地；持续地6．existence n. 生存；存在→exist vi. 存在7．contribution n. 贡献→contribute v. 贡献；撰稿8．consume vt. 消费；消耗；耗尽；吃完→consumer n. 顾客9．growth n. 增长；生长→grow v. 增长；生长10．educator n. 教育工作者；教育家→educate v. 教育→education n. 教育11．disagreement n. 分歧；不一致→disagree vi. 不同意；意见不合语境活用———————(用所给词的适当形式填空)1．The air conditioners of this type consume too much electricity. Many consumers complain about this. (consume)2．It was stated that the president made a statement announcing new policies to deal with the new situation. (state)3．They have contributed a lot of food and clothing to the refugees so far and their contributions will certainly help the refugees live through the winter. (contribute) 4．The young man whose parents are both educators,_is well educated. His parents received good education in a foreign country. (educate)Ⅱ.课标短语短语速记1．come_about 发生；造成2．subscribe_to 同意；赞成；订购3．quantities_of 大量的4．go_up 上升；增长；升起5．result_in 导致6．be_opposed_to 反对……7.even_if 即使8．keep_on 继续9．on_the_whole 大体上；基本上10．on_behalf_of 代表……一方；作为……的代言人11．put_up_with 忍受；容忍12．so_long_as 只要13．and_so_on 等等语境活用—————(选用上面的短语填空)1．The traffic accident resulted from the driver's carelessness, resulting_in the death of 3 people.2．With the house prices going_up,_more and more people can't afford an apartment. 3．It is the teacher as well as the students who subscribes_to the idea that we should do something for the poor old man.4．We are still wondering how it came_about that the experiment ended in failure. 5．What I can't put_up_with is that he never cares about others' feelings.6．I took part in a national speaking contest on_behalf_of our school and won first place.Ⅲ.重点句型教材还原1．It's OK to leave an electrical appliance on so _long _as you are using it—if not, turn it off!只要你在使用电器设备，你便可以把它开着。
2019高考英语一轮达标Unit4Globalwarming练题含解析新人教版选修620180917198
Global warming李仕才一、阅读理解。
Priscilla Ouchidas' “energyefficient” house turned out to be a horrible dream.When she and her engineer husband married a few years ago，they built a $100 000，threebedroom home in California.Tightly sealed to prevent air leaks，the house was equipped with small doublepaned windows and several other energysaving features.Problems began as soon as the couple movedin，however.Priscilla's eyes burned.Her throat was constantly dry.She suffered from headaches and could hardly sleep.It was as though she had suddenly developed a strange illness.Experts finally traced the cause of her illness.The level offormaldehyde(甲醛)gas in her kitchen was twice the maximum allowed by federal standards for chemical workers.The source of the gas? Her new kitchen cupboards and walltowall carpeting.The Ouchidas are victims of indoor air pollution, which is not given sufficient attention partly because of the nation's drive to save energy.The problem itself isn't new.“The indoor environment was dirty long before energy conservation came along，” says Moschandreas, a pollution scientist at Geomet Technologies in Maryland.“Energy conservation has tended to accentuate the situation in some cases.”The problem appears to be more troublesome in newly constructed homesrather than old ones.Back in the days when energy was cheap，home buildersdidn't worry much about unsealed cracks.Because of such leaks，the air in an average home was replaced by fresh outdoor air about once an hour.As aresult，the pollutants generated in most households seldom build up to dangerous levels.1．It can be learned from the passage that the Ouchidas' house ________.A．is well worth the money spent on its constructionB．is almost perfect from the point of energy conservationC．failed to meet energy conservation standardsD．was designed and constructed in a scientific way2．What made the Ouchidas' new house a horrible dream?A．Lack of fresh air.B．Poor quality of building materials.C．Gas leakage in the kitchen.D．The newly painted walls.3．Why were cracks in old houses not a big concern?A．Because indoor cleanness was not emphasized.B．Because they were technically unavoidable.C．Because environmental protection was more important.D．Because energy used to be inexpensive.4．This passage is most probably taken from an article entitled“________”．A．Energy ConservationB．Houses Building CrisisC．Air Pollution IndoorsD．Traps in Building Construction【解题导语】本文是一篇说明文，介绍了Ouchida夫妇响应国家号召建造了节能的房子，但是因为房子密不透风，使室内缺少新鲜空气，而且甲醛含量超标，室内空气污染，导致他们的身体出现了状况。
(全国通用)2019高考英语一轮复习 滚动测试4 新人教版.doc
（全国通用）2019高考英语一轮复习滚动测试4 新人教版第一部分听力(共两节,满分30分)第一节(共5小题;每小题1.5分,满分7.5分)听下面5段对话。
每段对话后有一个小题,从题中所给的A、B、C三个选项中选出最佳选项,并标在试卷的相应位置。
听完每段对话后,你都有10秒钟的时间来回答有关小题和阅读下一小题。
每段对话仅读一遍。
1.What does the man think of Baymax?A.A boring film.B.A dying robot.C.A perfect companion.2.When is the clinic open?A.From Monday to Friday.B.During the whole week.C.At weekends.3.What does the woman suggest?A.The radio batteries have been replaced.B.They should get a new radio.C.They don’t really need to listen to the radio.4.Where does the woman want to go?A.To Oxford.B.To Liverpool.C.To London.5.Who says organic food tastes better?A.Joe.B.The woman.C.Lucy.第二节(共15小题;每小题1.5分,满分22.5分)听下面5段对话或独白。
每段对话或独白后有几个小题,从题中所给的A、B、C三个选项中选出最佳选项,并标在试卷的相应位置。
听每段对话或独白前,你将有时间阅读各个小题,每小题5秒钟;听完后,每小题将给出5秒钟的作答时间。
每段对话或独白读两遍。
听第6段材料,回答第6、7题。
6.Why doesn’t the woman take her dog with her?A.She can’t take care of it.B.Her parents don’t want her to take it.C.She thinks the dog wouldn’t be happy there.7.Where do her parents live?A.In a big city.B.In a small village.C.In a nearby country.听第7段材料,回答第8至10题。
全国卷2019届高考英语一轮复习Unit4Earthquakes课时作业新人教版必修1.doc
Unit 4 EarthquakesⅠ.阅读理解APeople love cellphones ， which is why nine in ten Americans own one.But does heavy use of cellphones pose a risk of cancer? This question has caused controversy for many years.A new study in rats now augments those concerns.Its data linked long-term， intense exposure to radiation from cellphones with an increased risk of cancer in the heart or brain.The resultshave yet to be confirmed，the authors note.Indeed ，although the rat study found a link between cellphone radiationand cancer ，it offers no clues to why such a link might exist， notes Jonathan Samet.He teaches preventative medicine and directs the Institute for Global Health at the University of Southern California in Los Angeles.Still，he calls the new study's findings“ significant．They could” lead to studies researching how cellphone radiation might cause cancer，he says.Phone signals are relayed between cell towers and cellphones via radio waves.This radio frequency — or RF— radiation is a type known as non-ionizing( 非电离的 )．Unlike X-rays ，non-ionizing radiation does not deposit enough energy into cells to release electrons from atoms or molecules ，producing ions. So it tends to be far less harmful than ionizing radiation，such as X-rays.But that does not mean radio waves might not cause harm.In very large doses(量) this radiation will heat the body and cause tissue damage.But it's not yet known what much lower RF levels might do，such as those from cellphone use.Five years ago ，the World Health Organization's International Agency for Research on Cancer ， or IARC ， concluded that cellphone use“ is possibly carcinogenic (致癌的)”．Its conclusion was based on what little research data was available at that time.But notice that IARC was not certain.It said only that phone use might“ possibly ” cause cancer.So scientists at the National Toxicology Program ， or NTP ，investigated further.[语篇解读 ] 本文是一篇说明文。