2 . Directions: Fill in each blank with a proper word chosen from the box.Each word can only be used once.Note that there is one word more than you need.

A.reliance B.sought C.process D.contributing E.scalable F.delivered G.feasible H.efficient I.positioned J.occurring K.significant

New Path to Plastics

A crucial component could come from existing carbon sources.Ethylene (乙烯)is the world's most popular industrial chemical.Consumers and industry demand 150 million tons every year, and most of it goes into countless plastic products, from electronics to textiles.To get ethylene, energy companies crack hydrocarbons (碳氢化合物)from natural gas in a process that requires a lot of heat and energy,    1     to climate change - causing emissions.

Scientists recently made ethylene by combining carbon dioxide gas, water and organic molecules (分子)on the surface of a copper catalyst (催化剂)inside an electrolyzer - a device that uses electricity to drive a chemical reaction.The    2    , described last November online in Nature, could point the way toward using carbon dioxide as feed-stock for chemicals and potentially fuels, helping to reduce     3    on fossil fuels and to put a dent in industrial carbon emission.

The discovery grows out of work published last year by University of Toronto engineer Ted Sargent, describing a similar process that used more electricity and was less     4    overall.So Sargent says he     5    out researchers at the California Institute of Technology who are "black belts in molecular design and synthesis."

Caltech chemists Jonas Peters and Theodor Agapie and their colleagues experimented with organic molecules to add to the copper catalyst.An arylpyridinum salt turned out to be the Goldilocks molecule, Sargent says it formed a water-insoluble (不溶于水的)film (薄膜)on the copper that     6    the carbon dioxide so its molecules reacted most efficiently with one another, without slowing down the reaction.The result was more ethylene, with fewer by-products such as methane (甲烷)and hydrogen.

Still, the process must become even more efficient before it can be commercially     7    and use carbon scrubbed or captured from facilities such as coal-or gas -burning power plants.Lower energy costs, already    8     with renewable energy sources such as wind, could also help make it more     9    .

"This is a(n)     10    breakthrough," says Randy Cortright, a senior research advisesr at the National Renewable Energy Laboratory in Golden, Colo., who was not involved in the study.This result, he says, is "something that a lot of people are going to pay attention to, and they're going to be able to build on."

3 . Hunting to Farming Is Not Necessarily Good

A. support          B. effectiveness             C. expanding       D. escape             E. reached          F. questioning          G. switched                 H. control             I. recording        J. allowed        K. inferring

Shifting from hunting to farming made life 50 percent more difficult for humans, a study by Cambridge University suggests. Although farming     1    previously wandering communities to stay put and grow, it came at a huge cost. Researcher Dr. Mark Dyble, lived with 10 Agta groups and found that those who still hunted and searched for their food spent around 20 hours working in the week to live, but those who had    2     to farming needed to work 30 hours for the same amount of food.

“For a long time, the shift from hunting to farming was assumed to represent progress, allowing people to    3    a laborious and uncertain way of life,” said Dr. Dyble, “But as soon as researchers started working with hunter-gatherers they began     4     this narrative, finding that hunters actually enjoy quite a lot of leisure time. Our data provides some of the clearest     5    for this idea yet.” The researchers followed 359 people from the Agta community     6     how much time they spent on leisure, childcare, domestic chores and out-of-camp work. As well as the overall difference in hours worked, the study also found that women living in the communities most involved in farming had half as much leisure time as those in communities which only hunted. Co-author, Dr. Abigail Page added: “We have to be really careful when     7     from contemporary hunter-gatherers to different societies in pre-history.” But if the first farmers really did work harder than hunters then this begs an important question-why did humans adopt agriculture?

Previous studies suggested the adoption of farming grew up to help cope with    8    societies, although other experts claimed that it was agriculture itself that allowed sedentary (定栖的) communities to expand, and once they    9     a certain size, it would have been impossible for groups to return to a hunter-gathering lifestyle, even if they had wanted to. Dr. Page says: “The amount of leisure time that Agta enjoy is evidence to the    10    of the hunter-gatherer way of life. This leisure time also helps to explain how these communities manage to share so many skills and so much knowledge within lifetimes and across generations."

4 . Direction: Fill in each blank with a proper word chosen from the box. Each word can be used only once. Note that there is one word more than you need.

A.increasing 　　　　B.defend　　　　 C.partially 　　　　D.depriving E.sharpened　　 　　 F.breaks 　　　 　G.endured 　　　　H.granting I.issues 　　　　　　J.activate 　　　　K.roughly

Flood-hit Venice’s shrinking population faces mounting problems

Venetians(威尼斯人) are fed up with what they see as inadequate responses to the city’s mounting problems: record-breaking flooding, environmental and safety threats from cruise ship traffic and the burden on services from over-tourism.

They feel largely left to their own devices, with ever-fewer Venetians living in the historic part of the city to    1    its interests and keep it from becoming mainly a tourist land.

The historic flooding this week---marked by three floods over 1.5 meters (nearly 5 feet) and the highest in 53 years at 1.87 meters(6 feet, 1 inch)---has    2    calls to create an administration that recognizes the uniqueness of Venice, for both its concentration of treasures and its    3    vulnerability.

Flood damage has been    4    estimated at hundreds of millions of Euros (dollars), but the true range will only become clear with time. The frustration goes far beyond the failure to complete and    5    78 underwater barriers that were designed to prevent just the kind of damage that Venice has    6    this week. With the system not yet completed or even    7    tested after 16 years of work and 5 billion Euros ($5.5 billion) invested, many are suspicious it will even work.

At the public level, proposals for better administering the city including    8    some level of autonomy(自制) to Venice, already enjoyed by some Italian regions like Trentino-Alto-Adige with its German-speaking minority, or offering tax    9    to encourage Venice’s repopulation.

Just 53,000 people live in the historic part of the city that tourists know as Venice, down by a third from a generation ago and dropping by about 1,000 people a year. That means fewer people watching the neighborhood, monitoring for public maintenance    10    or neighbors in need. Many leave because of the increased expense or the daily difficulties in living in a city of canals, which can make even a simple errand a hard journey.

5 . Directions: Complete the passage with the words given in the table. Each word can be used only once. There is an extra one that you will find no use for.

A. evidence     B. significantly     C. completely       D. effective     E. remove F. applicable   G. beneficial        H. environment     I. assess          J. influence       K. purify

Can Indoor Plants Really Purify the Air?

Plants are very important to human life. Through photosynthesis (光合作用), they transform carbon dioxide into fresh oxygen. They are said to     1     toxins from the air we breathe — but is this true?

One famous NASA experiment, published in 1989, found that indoor plants can clean the air by removing cancer-causing pollutants like formaldehyde and benzene. Later research has found that soil micro-organisms in potted plants also play a part in cleaning indoor air.

Based on this research, some scientists say house plants are     2     air purifiers, and the bigger and leafier the plant, the better. “The amount of leaf surface area can     3     the rate of air purification,” says Bill Wolverton, a former NASA research scientist who conducted that 1989 plant study.

Other experts, however, say the     4     that plants can effectively accomplish this feat is far from conclusive.

“There are no definitive studies to show that having indoor plants can     5     increase the air quality in your home,” says Luz Claudio, a professor of environmental medicine and public health at the Icahn School of Medicine at Mount Sinai. There’s no question that plants are capable of removing volatile chemical toxins from the air “under laboratory conditions,” according to Claudio. But in the real world — in your home or in your office space — the notion that putting a few plants together can     6     your air doesn’t have much hard science to back it up.

Most research efforts to date, including the NASA study, placed indoor plants in small, sealed environments in order to     7     how much air-purifying power they have. But those studies aren’t really     8     to what happens in a house, says Stanley Kays, a professor of horticulture at the University of Georgia.

In many cases, the air in your home     9     turns over — that is, exchanges places with outdoor air — once every hour. “In most instances, air exchange with the outside has a far greater effect on indoor air quality than plants,” Kays says.

Many people may be disappointed by what Kays said, but the professor also made it clear that he believes house plants are     10     — they are not only pleasant living companions, but also provide a number of health benefits. Studies have shown plants can knock out stress by calming the sympathetic nervous system, and can also make people feel happier. More research shows spending time around nature has a positive effect on a person’s mood and energy levels.

6 . Directions: Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.

A. alarming       B. properties     C. revealed     D. invasive       E. rescue     F. instrumental G. households   H. document     I. concerned     J. amateur       K. initiatives

Before science became professionalized in the 19th century,     1     naturalists were collecting information and helping us understand the natural world. A 2009 study found that nearly 50% of UK     2     feed wild birds. The National Trust has more than 5 million members, and 60,000 active volunteers helping to protect the countryside as well as historic     3    . Now, with our environment arguably under greater threat than ever and species declining at a(n)     4     rate, volunteers are once again at the forefront of efforts to limit the damage.

Volunteers and enthusiasts can be powerful drivers for big changes. On the Isle of Man, more than 8,000 people (nearly 10% of the population) are involved in regular weekend beach cleans. At one recent event, 123 volunteers turned up and removed 183 bags of litter in just a couple of hours. Thanks to     5     such as this, the island shares Unesco biosphere reserve status with the Galápagos, Yellowstone in the US, Uluru in Australia, and hundreds of other sites.

Recreational divers are making a real difference underwater too. They monitor the spread of     6     species, and record how native species respond. Divers also     7     levels of marine litter and other human impacts. Volunteer divers have played an important role in collecting information about marine conservation zones. Volunteers have also made a vital contribution to the conservation of basking sharks. The work of a citizen science Basking Shark Project in the 1980s and 90s was     8     in getting these sharks on the protected species list in the UK, while satellite tagging     9     the first recorded transatlantic crossing by a basking shark.

Volunteers and enthusiasts can be powerful drivers for big changes. No one can know better, or care more about, our most special places than the people who live in them and give up their free time to look after them. As a group of divers and     10     residents who lived on the shores of the bay, they took their campaign on to national and international stages and continue to inspire people who might otherwise feel powerless when faced with threats to the places that matter to them.

7 . Directions: Fill in each blank with a proper word chosen from the box. Each word can be used only once. Note that there is one word more than you need.

A. approach   B. architectural   C. captured   D. complicated   E. defensive   F. defined G. extension   H. houses   I. reflect   J. shades   K. status

Why India’s ‘Pink City’ is a Photographer’s Heaven

The city of Jaipur is one of India’s wonders. It     1     some of the country’s most decorative royal palaces—elegant structures designed hundreds of years ago that still attract visitors today. Largely built in the 1700s, Jaipur is surrounded by a city wall and several     2     castles. Considered as a commercial center, it was ahead of its time due to the use of grid iron (网格状)city planning.

A romantic dusty pink type—which has     3     the city since 1876, after it was painted pink to welcome Queen Victoria’s husband, Prince Albert—gives Jaipur its     4     as the “Pink City”. This     5     beauty is what first brought Hong Kong-based photographers Victor Cheng and Samantha Wong to Jaipur.

Walking in glass skyscrapers for century-old royal palaces and historic castles, the pair—who have 130,000 Instagram followers between them—said that the images they     6     in Jaipur received a lot of response online. “A lot of our followers hadn’t seen this side of India, so we’re happy we were able to show this side of the country.” Cheng said.

For the photographers, one of the city’s most fascinating features is the light pink coloring of its buildings. “The first gates you see when you enter are pink,” said Wong. “Once you’re through, everything around you varies in different     7     of the color—from bright pinks to reddish browns.”

The building is a(n)     8     of the City Palace, and its windows allowed royal women to observe street life without appearing in public. One of Cheng’s most striking photos shows a straight front of the building and its hundreds of windows. The building’s lively coloring also pushed Cheng to take a different     9     to editing than with images of other cities. “I toned down my usual editing process because the pink was so bright in reality,” he said, “I wanted the photos to     10     the actual color I was seeing myself and to maintain its tone.”

8 . Directions: Fill in each blank with a proper word chosen from the box. Each word can only be used once. Note that there is one word more than you need.

As the increased amount of carbon dioxide in the atmosphere, heat stress, longer droughts(干旱), and more intense rainfalls linked to global warming continue to upset our daily weather, we often forget they also     1     the quantity, quality, and growing locations of our food. Many foods have already     2     top spots on the world's "endangered foods" list, indicating their possibility to become scarce within the next 30 years.

To start with what is     3     in many people’s lives, we are disappointed to find that coffee plantations in South America, Africa, Asia, and Hawaii are all being threatened by rising air temperatures and erratic(不稳定的) rainfall patterns, which invite disease and invasive species to     4     the coffee plant and beans. The result?

Significant cuts in coffee output. And Coffee's culinary cousin, cacao (aka chocolate), is also suffering stress from global warming's rising temperatures. But for chocolate, it isn't the warmer climate alone that's the problem. Cacao trees actually prefer warmer climates as long as that warmth is paired with high humidity and     5     rain. However, the problem is that the higher temperatures projected for the world's leading chocolate-producing countries are not expected to be    6    by an increase in rainfall. Therefore as higher temperatures take more moisture from soil and plants, it's unlikely that rainfall will increase enough to make up for this loss.

A notably nutritious plant, the peanut grows best when it gets five months of continuous warm weather and 20 to 40 inches of rain. Anything less and plants won't survive. That isn't good news when most climate models agree that the climate of the future will be one of the     7    , including droughts and heatwaves.

The world has already caught a glimpse of the peanut's future fate when last year a serious drought across the peanut-growing Southeastern U.S. led many plants to die.

According to a financial report, the dry     8     caused peanut prices to rise by as much as 40 percent!

Finally, in the world of sea, as air temperatures rise, oceans and waterways absorb some of the heat and undergo warming of their own. The result is the     9    in fish population. Warmer waters also encourage vicious marine bacteria, like Vibrio, to grow and cause illness in humans.

And that satisfying "crack" you get when eating crab(蟹) could be     10     as shellfish struggle to build their calcium carbonate (碳酸钙) shells, a result of ocean acidification.

9 . Directions: Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.

There’s nothing more annoying than settling down to sleep and hearing the sound of a mosquito buzzing around you.

The only thought most of us ever give to this noise is “I need to get rid of this insect, immediately”, but it turns out that the mosquito is actually quite a(n)     1     creature.

A team of scientists from Oxford University in the UK, in     2     with the Royal Veterinary College in London and Chiba University in Japan, recently published a study that found some interesting facts about the world’s most     3     insect.

By placing eight cameras inside a tiny film studio, the scientists could study several mosquitoes up close. The high-tech cameras filmed the insects at 1,000 frames per second, meaning the scientists were able to study the insects’     4     in never-before-seen detail. However, it wasn’t always straightforward.

“Recording mosquitoes during free-flight represented a huge technical challenge due to their small size,     5     wing beat frequency, and the presence of large antennae and legs that can     6     the view of their wings,” Simon Walker of Oxford University, co-author of the study, wrote.

Published in the journal Nature, the study found that mosquitoes flap their wings around 800 times a second. As a     7    , house flies flap their wings about 200 times a second, and hummingbirds 50 times a second.

Richard Bomphrey of the Royal Veterinary College, the study’s leader, believes that mosquitoes have a unique flying method that sets them apart from other flying insects.

“We predicted that they must make use of clever tricks, as the wings     8     their direction at the end of each half-stroke.” he wrote in the study.

Hopefully, the discovery of the mosquito’s special abilities will be of benefit to engineers in the future. The findings could lead to better aircraft, or even improvement to tools like lenses or pumps.

But the scientists hope their study can one day be     9     to new developments in more human-focused use.

“The more we know about mosquitoes, the better our chance of understanding their flight behavior, how they carry disease and     10     how to stop them from doing so,” Walker wrote.

10 . Directions: Fill in each blank with a proper word chosen from the box. Each word can be used only once. Note that there is one word more than you need.

Mentally and Intellectually Harmful

Last month, the Indian Medical Association declared a public health emergency in New Delhi because of high levels of air pollution. Schools were shut and emergency traffic restrictions put in place.

New Delhi is far from alone. Our research into the    1     of air pollution in China shows that, in addition to the more obvious physical price, air pollution can also have serious negative effects on mental health and cognition (认知),    2     reducing a person’s happiness and their scores in verbal and mathematical tests.

Such harmful mental effects have serious negative consequences for livelihoods and human capital development, suggesting that development    3     should go beyond the traditional focus of boosting GDP in the developing world.

India's recent pollution emergency is the most    4     incidence(发生率)of dangerous air pollution, but smoggy skies have been a cause of growing    5     in most developing countries.

Major cities across the developing world---from Thailand to Brazil, to Nigeria---    6     experience pollution at several times the WHO safe limits. In fact, 98% of cities with more than 100.000    7     in low and middle-income countries fail to meet the WHO’s air quality guidelines.

India’s extreme levels of air pollution are well recognized, and examining the effects provides clear warnings for other countries seeking fast growth through rapid industrialization.

We used nationally     8     longitudinal (纵向)surveys on mental health and cognition, matched with daily air quality data for the time and place of interviews, to see what pollution does in a given time to individual happiness and cognitive performance. Because each person in our survey was     9    multiple times, we can control for the effect of individual characteristics on the outcome variables.

We found that worsening air quality led to a decrease in happiness that day    10    to about 10 percent of the reduced happiness one would experience form a negative major life event such as divorce.