1 . Directions: Complete the following passages 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. selected        B. distinctive     C. signature       D. odds     AB. domestication       AC. decided AD. individuals   BC. tamest     BD. conflicted     CD. mixed     ABC. develop

If you see a house cat, the    1    are high that it will have white paws, a look that many owners affectionately call“socks.” But socks are rarely seen in wildcats, the elusive and undomesticated cousin of the house cat, so why do so many pet cats sport furry white feet?

As it turns out, this story started about 10,000 years ago, when humans and cats     2       life was better together.

This    3    eventually led to uber-prevalent socks on cats, as well as other well-known coat patterns, said Leslie Lyons, professor emerita and head of the Feline Genetics Laboratory at the University of Missouri College of Veterinary Medicine.

“As humans became farmers and started staying in one place, they had grain stores and waste piles” that attracted rodents, Lyons said. It was a mutually beneficial arrangement: the humans had fewer rodents to deal with and the cats got an easy meal.

The wild, undomesticated ancestor species of house cats, Felis silvestris, lives in Africa and Eurasia. These felines are tasty snacks as kittens and stealthy predators as adults, so     4     born with a coat that offers camouflage (保护色) have tended to survive and reproduce.

But not every F. silvestiis is born with a coat that blends into its habitat.

“Genetic mutations are occurring all the time.” Lyons said.

There isn’t much evidence to indicate why early cat people chose the individuals they did, but Lyons said the range of coats seen on modern domestic cats shows that our agrarian ancestors favored cats with markings that would have     5    with their camouflage.

In its native mixed forest or scrub desert environment, a cat with stark white paws would have stood out to predators and prey.

When humans started taking an interest in cats, these white paws would have stood out to them, too. “There were probably people saying, ‘I particularly like that kitten because it has white feet . Let’s make sure it survives’”, Lyons said.

Humans probably also    6    cats who were calm and comfortable around humans, Lyons said. Behavioral traits seem unrelated to coat color, but for reasons that scientists don’t fully understand, white spots tend to appear when the     7    individuals are selected and bred.

These    8    fur colors and markings emerge while a cat embryo is developing. The cells that give cat fur its color first appear as neural crest cells, which are located along what will become the back, Lyons said.

Then, those cells slowly migrate down and around the body. If those waves of cells move far enough to meet each other on the cat’s front side, the embryo will be born a solid-colored kitten, such as an all-black or all-orange cat. Felines     9    white feet, faces, chests and bellies when these cells don’t quite make it all the way.

So, the next time you see a kitty wearing white socks, you’ll know that this     10     feature is a result of genetic mutations, domestication and developmental biology. Although if you try telling the cat that, it will probably just look at you quizzically before sauntering away.

2 . 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．efficiency             B．employ             C．effective             D．chemicals             E．accelerating F．existing             G．projected             H．trapped             I．power                    J．simultaneously K．artificially

This past July was the hottest recorded month in human history. Heat waves smashed temperature records worldwide and even brought summer temperatures to Chile and Argentina during the Southern Hemisphere’s winter. It’s more than just a matter of sweaty discomfort. In the U.S. alone, it kills more people each year than floods, tornadoes and hurricanes combined. As climate change worsens, access to     1     cooled spaces is rapidly becoming a health necessity.

Yet standard air-conditioning systems have     2     us in a vicious cycle: the hotter it is, the more people use the AC—and the more energy is used as a result. Nicole Miranda, an engineer researching sustainable cooling at the University of Oxford says: “it’s not only a vicious cycle, but it’s a(n)     3     one.” According to 2018 data from the International Energy Agency (IEA), the worldwide annual energy demand from cooling is     4     to more than triple by 2050.

It’s becoming increasingly clear that humans cannot outrun climate change with the same air-conditioning technology we’ve been using. One well-known problem with current AC systems is their reliance on refrigerant     5    , many of which are potential greenhouse gases. About 80 percent of a standard AC unit’s climate-warming emissions currently come from the energy used to     6     it, says Nihar Shah, director of the Global Cooling Efficiency Program at Lawrence Berkeley National Laboratory.

Standard air-conditioning systems     7     cool and dehumidify through a relatively inefficient mechanism: in order to condense water out of the air, they overcool that air past the point of comfort. Many new designs therefore separate the dehumidification and cooling processes, which avoids the need to overcool.

Even with some of the best technologies available, the gains in     8     alone might not be enough to offset the widely expected increase in air-conditioning use. It will not work to simply replace every     9     air conditioner with a better model and call it a day. Instead, a truly cooler future will have to     10     other strategies that rely on urban planning and building design to minimize the need for cooling in the first place.

3 . 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. carved          B. unknowingly            C. ecosystem          D. artificial          E. elemental F. changing       G. practically        H. wrinkled        I. unmoving          J. species       K. inspection

Magical Creatures: AN APPRECIATION OF AUTUMN MOTH (蛾)

Moths seem to have a bit of a bad reputation: to some they are ill indications or something scary, to others they are dull in comparison to our well-loved butterflies. But moths are an essential part of a(n)     1    , and important food sources for species like birds and bats. And for me, moths are far from dull.

My first meeting with an Angle Shades moth was nearly a non-encounter. I almost passed by without noticing it, thinking it was a fallen leaf on a fence post. But there was something about it that stopped me in my tracks. Its angular shape perhaps? Or the way it sat,     2    , despite the breeze. Closer     3     revealed cream and buff shell-shaped wings, painted with triangles of light pink and brown. Suddenly, it transformed from a(n)     4     leaf into a living thing before my eyes. I’ve been fascinated ever since.

The Canary-shouldered Thorn, with its hairy buttercup-coloured body and yellow and orange wings, reminds me of a fallen silver birch (白桦树) leaf. A night-flyer, it favours gardens and woodlands, and is often drawn to     5     light, meaning that your torch beam may be attracting moths as well as lighting your way in the dark. It’s also worth double-checking any leaves in farm houses, as these sheltered spots are a favourite hiding place of another overwintering     6    : the Herald moth. This elegant creature’s beautiful wings look as though they’ve been     7     by hand and painted with bronze.

There’s more to these imitators than fallen leaves. The Green-spotted Crescent, which     8     disappears on rough branches, has metallic green spots integrating with the moss (苔藓). Maybe I’ve already     9     crossed paths with one, though. As we dig out our big coats and slip on boots for walks beneath branches, how many moths are we missing? These clever creatures aren’t bad indications, but     10     parts of nature, with a gift for fancy-dress.

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

A. arrives       B. observable   C. boundless.       D. contained. E. distancing. F. expansion G. lies       H. parallel       I. perceiving       J. threads       K. volume

What Comes After Space?

Looking at a clear night sky you witness the vastness of space, which holds everything humans know to exist. To find out what     1     beyond a good place to start is to determine where the universe ends. However, the problem is that scientist are uncertain about where space ends or whether it ends at all.

The     2     universe

The furthest humans can see out into space,using all the technology currently available to us,is 46 billion light years (alight year is the distance that light can travel in one year,and is equivalent to about 9. 5 million million kilometres). The     3     of space that humans can see is called the visible universe. Beyond this, it remains a mystery whether it’s an expanse of more galaxies and stars or possibly the edge of the universe. Some think that the universe is     4    , meaning space goes on forever in every direction. In this case,there is nothing after space,because space is everything.

Moving further away

Experts have captured images of the entire Earth from space,and some astronauts have personally witnessed its beauty from orbit. Perhaps     5     the limits of the universe would also be possible too, if only humans knew where to go to look for it.

Another challenge is the universe’s rapid     6    . As galaxies move further away their light   takes longer to reach us. Eventually, some galaxies may be so distant that their light never     7    . This might imply that any edge— and whatever is on the other side — is increasingly     8     itself from us. Regardless of these uncertainties, scientists still spend a lot of time thinking about what comes after space.

Many universes?

It’s possible that there isn’t just one universe, and that our universe is just one small part of a “multiverse”. Perhaps our universe is     9     within its own distinct region of space, separated from others by vast expanses of nothingness. Or maybe     10     universes exist pressed tightly against each other. Getting an idea of the universe’s true shape may help astronomers find out whether it has an edge. What comes after that could be an even great mystery.

6 . 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. alarming B. carbon-intensive C. durability D. glued E. labels F. man-made G. manufacturing H. recycle I. redefine J. samples K. share

How sustainable are your sneakers?

Over the last five years the sneaker industry has grown rapidly and shows no sign of slowing down. The global athletic footwear market is expected to exceed 95 billion (USD) by 2025. According to the World Footwear Yearbook, over 24 billion pairs of shoes are produced annually. Among them sneakers account for the largest     1    . What are the environmental impacts of the rapidly growing sneaker industry?

Sneaker production is very     2    . A typical pair of running shoes produces about 13.6 kilograms of CO₂ emissions which is unusually high for a product that does not use electricity or require power-driving components.

These emissions mainly come from     3    . The majority of sneakers are made from plastic and/or plastic-like materials. All these petroleum-derived plastics produce a(n)     4     number of carbon dioxide.

Then why don’t we move away from the use of plastic? Since sneakers have to endure much more than a regular pair of shoes, the aspect of their     5     is very important when it comes to their overall performance. Unfortunately,     6     materials hold up better than natural ones. Plastic has made shoes better, lighter, faster, more comfortable, and more accessible to everyone worldwide. Another issue with sneakers today is that most of them are made by using a combination of different plastics     7     in a very complicated way, making them very hard to     8    .

The footwear industry is at least 10 years behind the rest of fashion in terms of environmental standards. Seven out of ten brands are having discussions on sustainability, yet only 40% of companies have a sustainability program in place. Big industry players (such as Adidas and Nike) and some smaller     9     are trying to reduce their carbon footprint in different ways.

Considering that close to 25 billion pairs of shoes were produced worldwide in the last year, it is clear that immediate action is very important. It is my hope that we consumers will     10     our relationship with fashion and think about the environmental impact of our shopping habits.

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. double          B. intense          C. pressures       D. stock          E. agriculture       F. trapped G. withdrawal     H. availability   I. drive             J. expanding     K. rising

Throughout history, people have fought bitter wars over political ideology, national sovereignty and religious expression. How much more     1     will these conflicts be when people fight over the Earth’s most indispensable resource water? We may find out in the not-too-distant future if projections about the     2     of water in the Middle East and other regions prove correct.

Less than three percent of the planet’s     3     is fresh water, and almost two-thirds of this amount is     4     in ice caps, glaciers, and underground aquifers too deep or too remote to access. In her book, Pillars of Sand-Can the Irrigation Miracle Last, Sandra Postel outlines three forces that     5     tension and conflict over freshwater. Using up the water “resource pie”. In India, the world’s second-most populous nation, with over 1 billion inhabitants, the rate of groundwater     6     is twice that of recharge, a deficit higher than in any other country. Although water is a renewable resource, it is not a(n)     7     one. The freshwater available today for more than 6 billion people is no greater than it was 2,000 years ago, when global population was approximately 200 million. (The current U.S. population is 287 million.)

Global     8     accounts for about 70% of all freshwater use. In five of the world’s most water-stressed, controversial areas the Aral Sea region, the Ganges, the Jordan, the Nileland and Tigris-Euphrates population increases of up to 75% are projected by 2025. With the fastest rate of growth in the world, the population of Palestinian territory will more than     9     over the next generation. Most experts agree that, because of geography, population     10     and politics, water wars are most likely to break out in the Middle East, a region where the amount of available freshwater per capita will decrease by about 50% over the next generation.

8 . 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. cause   B. cover   C. crises     D. edged   E. hammered   F. left G. rages   H. reason   I. response   J. spill     K. warnings

The Wilsons river broke its banks on the night of February 27^th while Lismore, a town of around 30,000 in New South Wales, was sleeping. Its residents snoozed through early-hours emergency     1     that “risk to life was approaching”. Within hours the town was submerged. Residents scrambled into their attics. Mothers carried children onto rooftops. An army of locals launched tin boats into the floods to save them. Four people died.

Eastern Australia has been     2     by what politicians call “once-in-1,000-year” flooding. It has already had a rainy summer because of La Niña, a phenomenon which triggers downpours there. Brisbane, Queensland’s capital, received almost 80% of its annual rainfall in less than a week in February, flooding 15,000 homes. As the rain     3     into northern New South Wales, it ripped up roads and drowned herds of cattle. Storms lashed Sydney on March 8 th , causing a dam to     4     over. Some 50,000 people in the state have been forced to evacuate.

Scientists are careful when blaming floods on global warming because everything from rainfall to urban development contributes to them. They disagree, too, about whether climate change is a factor in this kind of never-ending downpour. No matter the     5    , extreme weather is now a regular occurrence in Australia. In 2019 and 2020 vast lands of the country were torched in bushfires which destroyed more than 3,000 homes and killed 33 people. Unlucky towns such as Lismore have in recent years been hit by both fire and floods.

It does not help that the state and federal governments’     6     has been disorganized. When disaster strikes, official aid is often slow to come. In 2019 the federal government set aside almost A$4bn for a fund that would help it respond to     7     and prevent future ones. But it has spent hardly any of that money. It has now deployed the army and is dishing out cash to victims, but locals fume that they were     8     for days without power or fuel as supplies of food and water dwindled.

A debate now     9     about how or even whether places like Lismore should rebuild. Analysts think the floods might trigger insurance claims worth more than A$3bn. Expenses are already so high in disaster-prone towns that many locals can no longer afford     10    . “If we are going to start thinking every time there’s a natural disaster that we have to give up and leave because it’s too hard, then where are we going to live?” asks Lismore’s mayor, Steve Krieg. That is becoming a question for ever more Australians.

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.

A. adopted   B. approaching   C. demonstration D. expansion E. featured F. focus G. forecasted H. maintained I. nonrenewable J. optimistic. K. surviving

Earth Day Turns 50

About 20 million Americans turned out for the first Earth Day on April 22, 1970. Lectures and gatherings took place at more than 2,000 college campuses, 10,000 elementary and high schools, and thousands of other places across the country. Forty-two states     1     resolutions supporting Earth Day. It is sometimes described as, up to that time, the largest public     2     in history.

The lectures and literature surrounding the event     3     lots of depressing predictions about the future, which could be found in the book The Environmental Handbook. Its cover noted that it had been “prepared for the first national environmental teach-in.” Commissioned(委托) by the group Friends of the Earth, the book talked about the threats of rising population and exhaustion of     4     resources- Many of its contributors—let’s call them the Catastrophists―warned that even such actions as halving the number of human beings and stopping economic growth completely might not be enough to prevent the     5     ecological disasters.

A different group of researchers     6     that while economic growth and technological progress had created some ecological problems, these things also would be a source of solutions. Let’s call these folks the Prometheans. The economist Theodore Schultz argued in the Bulletin of the Atomic Scientists in 1972 that the     7     of modern agriculture would free up more land for nature. Other advocates of this more     8     outlook included the oceanographer Cy Adler, the economist Christopher Freeman, and Nature editor emeritus John Maddox, author of the 1972 book The Doomsday Syndrome.

Today, the Earth Day Network hopes a billion people across the world will participate in Earth Day 2020, where the 50th anniversary     9     will be on man-made climate change. Living as we do in the future that the Catastrophists and the Prometheans (灾变论者与开创者)    10    ,   now is a great time to look back at the claims made five decades ago.

10 . Directions: Complete the following passages 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. approach B. beneficiaries C. recently D. eliminates   E. nutrients F. practices G. irreparable   H. threat   I. undesirable   J. panic K. naturally

The Beneficial Effects of Forest Fires

Forest fires are undoubtedly a threat. In the mid-1900s, all forest burns were considered     1    , and firefighters responded to all of these fires whether or not they were burning close to where humans lived. This     2     to forest fires was both expensive and risky. However, more     3     forest managers began to see that forest fires did have benefits. Foresters saw that forest fires were beneficial for trees and soil.

Previously, people believed that forest fires caused     4     damage to trees, however, now forest managers know that trees are the major     5     of fires. Many     6     occurring forest fires, often caused by lightning strikes, are surface fires that burn the understory — the shrubs and herbs from the forest — without damaging the trees in the overstory. In this way, the fire     7     competition from the smaller trees, allowing the larger trees to flourish. Once the understory has been burned away, the forest is less likely to burn from high-temperature fires that can do real damage to the tall trees.

In the past, it was not obvious how forest fires enriched the soil. Today, foresters understand that forest fires improve soil quality by changing the ‘litter’ — dead leaves and branches on the forest floor — to nutrient-rich soil. Normally, litter decomposes very slowly. However, fire releases the     8     in the litter immediately. This creates an increase in the amount of phosphorus and potassium which are key elements that promote tree growth.

As forest managers have leared more about the long-term effects of forest fires, they have realized that forest fires can have beneficial effects and have changed their forest management     9     to reflect this new opinion. It is now recognized that forest fires, are a natural part of forest ecosystems and are beneficial to the trees and soil. As long as fires are no     10     to homes and communities, foresters now often choose to do nothing to stop the fires.