1 . When Mexican scientist of the evolution of animal behavior, Laura Cuaya, moved to Hungary for her postdoctoral studies in Budapest, she brought her pet dog, Kun-kun, along for the ride. Cuaya couldn't help noticing how locals warmed to dogs. This prompted her naturally curious scientific mind to start asking questions. “Here people are talking all the time to Kun-kun, but I always wonder if Kun-kun can recognize that people in Budapest speak Hungarian, not Spanish?” So she set out to find an answer through a scientific study.

Cuaya and her colleagues decided to use brain images from MRI scanning to shed light on her hunch. They worked with dogs of various ages that had, until the experiment, only heard their owners speak just one of the two languages, Spanish or Hungarian. Not surprisingly, getting the dogs to happily take part in the experiment took some creative coaxing and animal training! The researchers first needed to teach Kun-kun and her 17 fellow participating dogs including a labradoodle, a golden retriever and Australian shepherds, to lie still in a brain scanner. Their pet parents were always present, and they could leave the scanner at any point.

The research team played children's book classic The Little Prince in both Spanish and Hungarian while scanning the dogs' brains with an MRI machine. They were looking for evidence that their brains reacted differently to a familiar and unfamiliar language. The researchers also played scrambled versions of the story to find out if dogs could distinguish between speech and non-speech.

The images reveal that dogs' brains show different patterns of activity for an unfamiliar language than for a familiar one — the first time anyone has proved, researchers say, that a non-human brain can distinguish between two languages. This means that the sounds and rhythms of a familiar language are accessible to non-humans.

Interestingly, the team also found that the brains of older dogs were more skilled at detecting speech “suggesting a role for the amount of language exposure”. They suggest that dogs have refined their ability to distinguish between human languages over the long process of domestication.

1. What is paragraph 1 mainly about?

A．The background of the study.	B．The significance of the study.
C．The concern of the researcher.	D．The introduction to the researcher.

2. What did Cuaya consider when choosing dogs for study?

A．Age limits.

B．Brain patterns.

C．Language exposure.

D．Owners' commands.

3. The results of the study are ________.

A．practical

B．contradictory

C．compromising

D．groundbreaking

4. Which of the following can be the best title?

A．Dogs Can Tell Foreign Languages	B．Dog Brains Have Different Patterns
C．Old Dogs Know More About Human Speech	D．Dogs Can Differ Speech From Non-Speech

3 . Directions:Complete the following sentences by using the proper form of the words or expressions   given in the frame.Each one can only be used once.

A. capable        B. effectiveness       C. employing        D.exposure          E.famously           F. joining          G. limitation        H. minimal       I.precisely        J.recognizing       K.worthwhile

Clean Air Act

The air in modern homes and offices is pretty clean,but not as clean as it might be.Often it contains small amounts of volatile(挥发性的）,poisonous,organic compounds.Long-term    1     to these is a bad thing,so clearing them out of the air people breathe is widely accepted as     2    

Finding an effective way to do so has proved difficult.But Stuart Strand, Long Zhang and Ryan Routsong, of the University of Washington,in Seattle,think they have succeeded,As they report in Environmental Science and Technology, their method involves     3     a gene from a rabbit into a popular indoor plant nicknamed Devil's vine—a type of ivy hat is so called because it is    4     difficult to kill.

The idea of     5     plants to de- pollute   the atmosphere inside buildings has been around for decades-but has met with only qualified success. One experiment involving unmodified spider plants,for example,showed that they are indeed     6     of removing formaldhyde (甲醛) from the air.The     7     is that to make much of a difference in a space as large as a house would require turning most of the rooms into spider-plant forests.

Dr Strand, Dr Zhang and Mr Routsong thus sought something suitably transgenic ( 转 基 因 的),but that does not flower indoors. The plant they settled on was Devil's vine,     8     because of its toughness.With the help of a bacterium,they were able to ferry the rabbit version of the gene into the plant's chromosomes(染色 体),and thus to,engineer a type of Devil's vine able to produce an air-cleaning substance. To test the     9     of their idea, the researchers put their modified ivy to work inside greenhouses filled with air containing high levels of harmful substances.The plants performed well,reducing the harmful substances in air to     10    .

4 . For millions of years, Arctic sea ice has expanded and shrunk in a rhythmic dance with the summer sun. Humans evolved in this icy world, and civilization relied on it for climatic, ecological and political stability. But now the world comes ever closer to a future without ice. The National Snow and Ice Data Center reported that 2019’s minimum arctic sea ice extent was the second lowest on record. Arctic summers could become mostly ice-free in 30 years, and possibly sooner if current trends continue. As the northern sea ice declines, the world must unite to preserve what remains of the Arctic.

Although most people have never seen the sea ice, its effects are never far away. By reflecting sunlight, Arctic ice acts as Earth’s air conditioner. Once dark water replaces brilliant ice, Earth could warm substantially, equivalent to the warming caused by the additional release of a trillion tons of carbon dioxide (CO₂) into the atmosphere and declining sea ice threatens wildlife, from the polar bear to algae that grow beneath the sea ice, supporting the large amount of marine life.

To avoid the consequences the scientific community should advocate not just for lowering greenhouse gas emissions, but also for protecting the Arctic from exploitation. The Antarctic shows the way. In the 1950s, countries raced to claim the Antarctic continent for resources and military installations. Enter the scientists. The 1957-1958 International Geophysical Year brought together scientists from competing countries to study Antarctica, and countries temporarily suspended their territorial disputes (争议). In 1959, 12 countries signed the Antarctic Treaty to preserve the continent for peaceful scientific discovery rather than territorial and military gain.

Sixty years later, we must now save the Arctic. A new Marine Arctic Peace Sanctuary (MAPS) Treaty would protect the Arctic Ocean as a scientific preserve for peaceful purposes only. Similar to Antarctica, MAPS would prohibit resource exploitation, commercial fishing and shipping, and military exercises. So far, only 2 non-Arctic countries have signed MAPS; 97 more need to sign on to enact it into law. Scientists can help—just as they did for the Antarctic—by giving statements of support, asking scientific organizations to endorse (支持) the treaty, communicating the importance of protecting the arctic to the public and policy-makers, and above all, by convincing national leaders to sign the treaty. In particular, Arctic nations must agree that recognizing the arctic as an international preserve is better than fighting over it. In 2018, these countries successfully negotiated a 16-year moratorium on commercial fishing in the Arctic high seas, demonstrating that such agreements are possible.

Humans have only ever lived in a world topped by ice. Can we now work together to protect Arctic ecosystems, keep the northern peace, and allow the sea ice to return?

1. What can be inferred from the passage?

A．wildlife relies on sea ice for food and water.

B．The Arctic would be ice-free in 30 years.

C．Sea ice slows down the global warming.

D．The melting of sea ice releases CO2.

2. The Antarctic is mentioned in the passage in order to ________.

A．remind readers of the past of the Antarctic

B．propose a feasible approach for the Arctic

C．stress the importance of preserving sea ice

D．recall how the Antarctic Treaty came into being

3. The word “moratorium” (in paragraph 4) is closest in meaning to ________.

A．battle	B．ban
C．memo	D．protection

4. Which of the following might be the best title of the passage?

A．Antarctic: a Successful Comeback?	B．Sea Ice and Global Warming
C．Arctic: the Earth’s Future	D．Life Without Ice?

5 . In the 1966 science-fiction movie One Million Years B. C., the movie characters had a time travel and arrived in an ancient landscape inhabited by dinosaurs and early humans. The movie was low on science and high on fiction: by then dinosaurs were long dead and modern humans were millions of years away.

A more accurate picture of Earth’s inhabitants at the time is now being revealed. In research published in Nature, a team of scientists led by Anders Gotherstrom at the University of Stockholm, and Love Dalen at the Centre for Palaeogenetics (古遗传学), also in Sweden, describe sequencing (测序) DNA samples from mammoths (猛犸象) that lived and died in north-eastern Siberia around a million years ago.

The team’s work represents a new record, for their mammoth DNA is, by some half a million years, the oldest ever successfully reconstructed. Extracted (提取) from horses, bears and even Neanderthals and Denisovans, two close cousins of modern humans, such ancient DNA has proved an invaluable tool for investigating the past. Although fossils preserve the basic physical features of extinct animals, they are silent about many crucial details that even an incomplete genome (基因组) can help to fill in.

The trouble with DNA is that it breaks down after death. The more broken down it is, the harder it is to sequence. Scientists think that, after about 6m years, all that would be left would be individual base pairs (碱基对), the equivalent of trying to reconstruct a book from several letters. Under the right conditions, however, such as the extreme cold of Arctic permafrost (冻土层) this decay can be slowed.

Dr. Dalen and his colleagues were interested in three mammoth molars (臼齿) extracted in the 1970s from Siberian geological layers that suggested great age. Samples from each were sent to Dr. Dalen’s laboratory in 2017. Having checked they had not been contaminated by bacteria or the shaking hands of Paleontologists, the DNA were extracted, sequenced, and dated. Whereas DNA samples from a living animal can run to several hundreds of thousands of letters, the ancient mammoth samples yielded merely dozens of letter long. This is close to the limit of what is scientifically usable, says a biologist named Ludovic Orlando.

1. What does the underlined word “contaminated” probably mean?

A．Protected.

B．Polluted.

C．Estimated.

D．Discovered.

2. According to the passage, the challenges the research team face may include ________.
①the limited number of DNA in mammoth samples
②the break-down of mammoth’s DNA after death
③the wide spread of mammoth samples
④the damage done to the mammoth samples from external environment
⑤the difficulty in extraction of the mammoth’s DNA

A．①②④

B．②④⑤

C．②③④

D．①③④

3. Which of the following statements is true according to the passage?

A．The fact that DNA can break down makes it easier to sequence.

B．The incomplete genome can’t give any details of the extinct animals.

C．Mammoths’ DNA samples are invaluable for their extremely long history.

D．The research team created a new record for reconstructing an ancient book.

4. What is the passage mainly about?

A．The movie One Million Years B. C revealed the early human civilization.

B．Scientists have uncovered the secrets of life by studying mammoths’ DNA.

C．The mammoths’ DNA may give a clearer picture of ancient inhabitants on earth.

D．Discoveries of mammoths’ DNA samples help the development of DNA reconstruction technology.

6 . 听下面一段独白，回答一下小题。
1.

A．In 1815.

B．In 1848.

C．In 1850.

D．In 1855.

2.

A．High school education.	B．Two-year study programs.
C．100 education programs.	D．Four-year college programs.

3.

A．California has the most state colleges and universities in America.

B．California is a large city with more than 4, 000, 000 people.

C．California is the largest state in land area throughout America.

D．California has only a few high-technology companies.