Ⅰ.阅读理解
A
People 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 results have yet to be confirmed，the authors note.
Indeed，although the rat study found a link between cellphone radiation and 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。人们喜欢用手机，90%的美国人都有手机。那么，过度使用手机是否会有患癌的风险呢？一项新的研究给出了一些线索。
1．Which of the following can replace the underlined word “augments”？ A．figures out
B．puts out
C．refers to D．adds to
解析：词义猜测题。画线词前面提到过度使用手机是否有患癌的风险这一问题多年来引发的争议不断，再根据画线词后的“concerns”和“Its data linked long-term，intense exposure to radiation from cellphones with an increased risk of cancer in the heart or brain.”可知，现在一项在老鼠身上进行的新研究增加了那些忧虑。故画线词与adds to意义相近。
答案：D
2．In which aspect does Jonathan Samet think the new study in rats is significant? A．It assists him with his teaching. B．It indicates a new research direction. C．It warns people to mind cellphone safety. D．It makes a breakthrough in cancer research.
解析：推理判断题。根据第二段中的“They could lead to studies researching how cellphone radiation might cause cancer，he says.”可知，这项研究会促使科学家去查明手机辐射可能是怎样致癌的，也就是说它为科学家提供了一个新的研究方向。
答案：B
3．What is Paragraph 3 mainly about? A．How phone signals are delivered. B．How cellphones produce radiation. C．Features of radiation from cellphones.
D．Differences between ionizing and non-ionizing radiation.
解析：段落大意题。根据第三段的内容尤其是“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...”可知，本段主要讲的是手机辐射的特点，它是非电离的，其危害性远低于电离辐射。
答案：C
4．What might be the theme of NTP scientists' further research? A．Why cellphone use causes cancer.
B．Whether cellphone use really causes cancer. C．What health effects cellphone use has.
D．How much exposure to cellphone radiation is safe.
解析：推理判断题。根据最后一段中的“It said only that phone use might ‘possibly’ cause cancer.So scientists at the National Toxicology Program，or NTP，investigated further.”可知，NTP的科学家进一步研究的主题可能是手机使用是否真的
会导致癌症。
答案：B
B
Ambar presses her hand to her forehead as she considers the question on her screen: how many sevens in 91? The ten-year-old has been struggling with it for about a minute when she smiles，“13！” Her tutor responds by posting a large smiling cat picture on her screen—the virtual(虚拟的) meaning of a pat on the back.He is sitting on the other side of the world in an online tutoring centre in India.
Ambar，who attends Pakeman Primary School in London，is one of nearly 4,000 primary school children in Britain that have signed up for weekly one-to-one maths sessions with tutors based in India and Sri Lanka.The lessons，provided by a company called Third Space Learning，are targeted at pupils struggling with maths—particularly those from disadvantaged backgrounds.
From next year，the platform will become one of the first examples of artificial intelligence (AI) software being used to monitor，and ideally improve teaching.Together with some British scientists，the company has analysed around 100,000 hours of audio and written data from its tutorials(辅导课)，with the goal of identifying what makes a good teacher and a successful lesson.
Tom Hooper，the company's CEO，said，“We've recorded every lesson that we've ever done.By using the data，we've been trying to introduce AI to improve the teaching.”But he argued that the aim is not to replace teachers with robots.“There's a slightly dubious(不确定的) conversation about how AI will make humans irrelevant，but it's not at all about replacing humans，”he said.“Our whole belief is that for children not doing well in the subject，people are what matters.”
Pupils on the program have a 45-minute session with the same tutor each week.They communicate through a headset and a shared “whiteboard”．The lessons at Pakeman Primary School are tailored to the individual，including visual rewards linked to the child's interests.In addition to the raw audio data，each lesson has various success metrics attached：how many problems are completed，how useful the pupil finds the session，how the tutor rates it.
[语篇解读] 本文是一篇说明文。数学成绩不好怎么办？没关系。坐在家里，你就可以享受高科技公司Third Space Learning为你提供的一对一网上教学服务。
5．Why does the author mention Ambar in the beginning? A．To praise her tutor.
2019届高考全国卷英语一轮复习课时作业：必修一 Unit
