1 . 听下面一段较长对话，回答以下小题。
1. What does Lily suggest Mr. Stenson doing?

A．Using the pesticide.

B．Changing the crop.

C．Watering the fields.

2. What do we know about Lily’s uncle?

A．He often shares his products.

B．He lives far from Lily.

C．He is good at farming.

2 . How Gardeners Can Reduce Risk of Fire

If you are selecting plants for your garden, knowing which plants offer some fire resistance and which are more flammable (易燃的) can serve you well.

Quicker to catch fire

Plants like bamboo that produce flammable substances such as aromatic oils, resins (树脂), wax, or sap, are among the quickest to catch fire.     1    

Trees with thin bark (树皮) that falls off are usually more flammable than those without. And fine-needled plants like pine, juniper, and spruce contain resins.     2    

Many kinds of grasses are highly flammable. Their ability to catch fire increases when they are left to stand dry over winter or during periods without rain. Additionally, too much heat dries out the soil and under such conditions, many kinds of plants turn into a fire starter.

Native vs. non-native

As a group, native plants aren’t necessarily less flammable than introduced kinds of plants.     3     That is because they spread quickly and are usually left alone by wildlife. The non-native plants spread faster than native plants, and often tolerate heat, heavy rain and lack of water better.

For the best fire resistance, choose trees that lose their leaves every year, like ash, and maple, rather than fine-needled trees.     4     Those plants with water-filled leaves include ice plants and sedums. Some groundcover plants are also slow burners.

What to look for in plants

The Washington State University Extension Service has published advice for choosing plants that are fire-resistant.     5     They include:

•High water content in leaves.

•Little or no seasonal gain of dead plant material.

•Open branching (they provide less fuel for fires).

•Fewer total branches and leaves.

A．Some plants are more flammable than others.

B．Plants with water-filled leaves are slow to burn.

C．But non-native plants often are a greater fire risk.

D．Many plants have qualities that do not burn easily.

E．All plants might catch fire under the right conditions.

F．Their needle-like leaves increase the risk of fire when left on the ground.

G．They will often catch fire even if they have been well-watered and cared for.

3 . In a new study, researchers found that invasive insects in the United States could kill approximately 1.4 million urban trees by 2050, which would cost over $900 million to replace, reports Vishwam Sankaran for the Independent.

Hot spots predicted to have the most urban tree mortality (死亡率) were Milwaukee, Wisconsin; Chicago, Illinois; and New York, New York. The study, published in the Journal of Applied Ecology, is the first nationwide forecast of street tree mortality from invasive insects.

The emerald ash borer is an invasive beetle native to Asia. It was first detected in 2002 in southeastern Michigan, and experts suspect it was brought into the United States on wood packing material carried on cargo ships or airplanes traveling from Asia. Since then, the bug has been damaging ash trees. In the last two decades since the insect was first detected, numerous trees have been killed in North America.

Data collected from 30,000 communities across the country was used to estimate tree mortality in the next 30 years. The researchers combined this data with a model that predicted the spread of 57 different invasive insect species. Their results show emerald ash borers alone could cause 90% of the estimated 1.4 million tree deaths. Ash borers are already predicted to “kill virtually all ash trees” in over 6,000 urban areas, according to Newsweek.

Less than 25% of 30,000 urban areas in the U.S. are expected to experience 95% of all street-tree mortality, reports Adam Barnes for the Hill. The areas that will experience the most tree loss include cities in the Midwest and East Coast. These locations are expected to have the most tree loss because large numbers of ash trees occupy the streets and parks in these areas, reported the Independent.

When it comes to how to save urban areas from becoming treeless, study author Emma Hudgins, a biologist at McGill University, says, “These results can hopefully provide a cautionary tale against planting a single species of tree throughout entire cities, as has been done with ash trees in North America. Planting various trees provides resilience against pest infestations (侵扰).”

1. What can we know about the emerald ash borer?

A．It is an invasive beetle in Asia.

B．It was first found by the Michigan people.

C．It has killed numerous trees in America.

D．They definitely enter the U.S. by cargo ships or airplanes.

2. What is the fourth paragraph intended to describe?

A．The purpose of the research.	B．The conclusion of the research.
C．The significance of the research.	D．The process and result of the research.

3. What can be inferred from the fifth paragraph?

A．Pest infestations are taking place across the country.

B．The insect’s invasion won’t spread equally in America.

C．Tree loss is the main cause of environmental problems.

D．Ash trees are being removed from many areas in the U.S.

4. What suggestion does Emma Hudgins provide?

A．Getting different types of trees planted.

B．Replacing foreign trees with local ones.

C．Getting more trees planted in more areas.

D．Planting trees resistant to pest infestations.

4 . In early October, Travis Gienger transported an enormous pumpkin (南瓜) from his home in Minnesota to the World Championship Pumpkin Weigh-Off in California. His pumpkin set the record for the biggest one ever grown in North America. How do competitive growers get their pumpkins to grow to massive sizes?     1    

Gienger, who teaches horticulture (园艺学) at Anoka Technical College, begins growing his pumpkins in mid-April, starting with seeds that he grows indoors for the first few weeks, when Minnesota’s soil is too frosty.     2     They can absorb sunlight, nutrients from the soil, and water there. “At their peak, you’re watering them with at least 600 liters a day, ” he says.

Depending on the variety, pumpkin plants can grow up to a dozen fruits on a single vine (藤曼) . But to maximize size, growers remove all but one or two of these pumpkins in order to decrease each individual fruit’s competition for resources.     3    

But what exactly happens inside a pumpkin as it grows? Two factors drive natural growth: cell division and cell expansion. Cell division accounts for most of the growth at the beginning of a fruit’s life. This period lasts for about 20 days in pumpkin plants.     4     Pumpkin cells will expand until around 50 or 60 days after pollination (授粉).

    5     Some varieties of pumpkins have been bred specifically to maximize their size. Still, there is genetic variation even among pumpkins of the same variety. This has led to competition for the best seeds. Following each harvest, many growers auction off (拍卖掉) the seeds from their biggest pumpkins, which will then be used for the following year’s plantings.

A．Biology has the answers.

B．Genetics also influences pumpkin growth.

C．The following tips will give you a head start.

D．Once it warms up, the plants are transferred outside.

E．When it stops, cell expansion will then come into play.

F．Growers extend the growth period for as long as possible.

G．Growers also remove the weeds in the area for the same reason.

5 . 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. chaos        B. consume        C. plentiful       D. discharge        E. evolutionarily     F. extent G. freeze   H. mechanism       I. novel          J. subsequently     K. unstable

Science in Images

Oyster mushrooms feature in cuisines around the world, but they should be off the menu for hungry worms -- which these delicious mushrooms will kill and eat. Now researchers finally know how they do it.

A study published in Science Advances details how oyster mushrooms use a particular poisonous substance to freeze and get rid of mushroom-eating roundworms called nematodes (线虫). The mushrooms, which grow on nutrient-poor dead wood, then     1     the worms for nutrition.

“Nematodes happen to be the most     2     animals these mushrooms encounter. So I think,     3    , this cross-kingdom interaction is very interesting,” says study senior author.

The study team of geneticists, biochemists and biologists had previously found that oyster mushrooms release an unidentified poisonous substance that will somehow     4     the worms within minutes and cause a chemical element to flow into their cells, killing them. This     5     differs from those used by other meat-eating mushrooms and could be unique to oyster mushrooms.

For their new work, the researchers grew and analyzed samples of the mushroom’s tissue, finding no noticeable poison even when they broke it up. They reasoned that whatever was killing the worms must be a kind of     6     compound that disappears into air when disturbed. When they damaged the oyster mushroom tissue again and     7     analyzed the nearby air, they finally found a nerve gas that turned out to be contained with tiny, special-shaped structures on the mushroom surface. When nematodes touch the mushrooms, these structures     8     their gas, disturbing the worms’ cell walls to cause immobility and death. The worm is then digested by the mushrooms.

Before this study, “we underestimated the     9     to which wild mushrooms defend against or consume nematodes,” notes Nick Talbot, a geneticist at Sainsbury Laboratory in Norwich, England. The study demonstrates “a very     10     approach,” he adds. “These organisms are really difficult to work on, and Dr. Hsueh is showing that you can do some really amazing work with them.”

6 . Keeping plants at home is a healthy and comfortable way of life. The following houseplants can create a most beautiful piece of green for your home.

Bird’s Nest Fern (蕨)

The bird’s nest fern is a good choice for anyone with a house that wouldn’t support sun-loving species. It’s a hardy fern variety adapting to living on forest floors, where the air tends to be cool and damp. It likes to be misted as well, but this doesn’t always mean you need a misting bottle—spraying (喷洒) it in the sink or hanging it near a shower often works as well.

Chinese Money Plant

This is a flowering species that might be most appropriate for experienced plant gardeners looking for a new challenge. It prefers a moderate amount of indirect light, and tends to dry out slightly between watering sessions. It produces new plants easily without any input, directly from its root system. These can coexist in the same pot for a time.

Resurrection Plant

This native of the Mexican desert has adapted to surviving in extreme drought by curling (蜷缩) into a ball and remaining in seemingly lifeless state for years, if necessary. In this form, it can be transported by the wind across the dry landscape to areas with water. It will revive within hours in a shallow bowl of water, unfolding and transforming into a fresh and green moss (苔藓).

Snake Plant

This is a striking houseplant that can be an especially good option for new plant owners who you might not trust to keep a plant alive. It grows happily in almost any condition. While it prefers bright light, it doesn’t mind shade or even artificial light. Plus, thanks to its thick, fleshy leaves, it stores water with remarkable efficiency, which makes it survive without water in the earth.

1. What is special about the bird’s nest fern?

A．It prefers shade.	B．It is sun-loving.
C．It tends to grow in the sink.	D．It can return to life after death.

2. Which plant will test its owner’s gardening skill most?

A．Bird’s nest fern.	B．Chinese money plant.
C．Resurrection plant.	D．Snake plant.

3. What do resurrection plant and snake plant have in common?

A．They demand attentive owners.	B．They are very drought-tolerant.
C．They will curl for self-protection.	D．They can store water for drought.

7 . A forest in Staffordshire (in the UK) transformed into a hi-tech laboratory. Researchers here are investigating how the trees use carbon, and it’s difficult to find out. In an unusual experiment, extra carbon dioxide is piped to the trees, to create the kind of atmospheric conditions expected in the middle of the century. And instruments measure how the forest reacts.       

The scientist in charge says there’s still a lot to learn. And he worries that governments and companies are rushing to plant trees as an easy answer to climate change. “If you try and use trees to tidy up the mess that we’re making through emissions, you are putting those trees into a very rapidly changing climate and they will struggle to adapt,” said Professor Rob MacKenzie, University of Birmingham.

This device tracks the movement of carbon dioxide. In a healthy forest, the gas is not only absorbed by the trees but some is released as well. What scientists here are finding out is the way carbon flows into a forest and out of it is a lot more complicated than you might think. So, if mass tree planting is meant to be a solution to tackling climate change, the trees are going to have to be monitored and cared for, over not just decades, but may be centuries as well.

Of all the challenges, the task of planting is the simplest. Shelby Barber from Canada can do an amazing 4,000 trees in a day. “People talking about planting millions billions of trees around the world. Is it possible do you think, physically?” asked BBC.

“It’s definitely possible with the right amount of people, the right group of people. I’ve personally, in three years, planted just over half a million trees.” said Professor Rob MacKenzie.

Once planted, the trees need to survive, and experts are mixing different types to minimize the risk of disease. “It’s a bit like making sure you don’t put all your eggs in one basket, you’re spreading out your risk. And then if one part of that woodland fails, for whatever reason, it gets a disease or it can’t tolerate future climatic conditions, there are other parts of the forest that are healthy and able to fill in those gaps.” said Eleanor Tew of Forestry England.

Suddenly there’s momentum to plant trees on a scale never seen before. So what matters is doing it in a way that ensures the forests thrive — so they really do help with climate change.

1. Why is extra carbon dioxide piped to the trees in the experiment?

A．To predict the future atmospheric conditions.

B．To imitate the possible air condition in the future.

C．To create an instrument to measure atmospheric conditions.

D．To investigate the quality of air condition in the future.

2. The underlined word “some” in the second paragraph refers to __________.

A．oxygen

B．carbon dioxide

C．mess

D．purified gas

3. What will Eleanor Tew suggest concerning the survival of the forest?

A．Minimizing the area of the woodland.

B．Studying future climatic conditions.

C．Planting different types of trees.

D．Avoiding mixing different species.

4. Which statement concerning mass tree planting will Professor Rob Mackenzie mostly likely agree with?

A．It should be advocated in terms of efficiency and convenience.

B．It is the most effective solution to fighting climate changes.

C．It will do more harm than good to the health of the environment.

D．It needs to be studied further as a measure against climate change.

8 . When lightning caused fires around California’s Big Basin Redwoods State Park north of Santa Cruz in August 2020, the fire spread quickly. Mild fires strike coastal redwood (红杉) forests about every decade. The giant trees resist burning thanks to the bark (树皮), up to about 30 centimetres thick at the base, which contains acids. Their branches and needles are normally beyond the reach of flames. But this time flames shot through the top of 100-metre-tall trees, burning the needles. “It was shocking,” says Drew Peltier, a tree expert at Northern Arizona University. “It really seemed like most of the trees were going to die.”

Yet many of them lived. In a paper published yesterday in Nature Plants, Peltier and his colleagues help explain why: The survivors use long-held energy reserves—sugars that had been made from sunlight decades earlier—and poured them into buds (芽) that had been lying dormant (休眠的) under the bar k for centuries.

“This is one of those papers that challenges our previous knowledge on tree growth,” says Adrian Rocha, an ecosystem ecologist at the University of Notre Dame. “It is amazing to learn that carbon taken up decades ago can be used to sustain its growth into the future.” The findings suggest redwoods have the tools to cope with big fires driven by climate change, Rocha says. Still, it’s unclear whether the trees could cope with the regular infernos that might occur under a warmer climate environment.

The fire in 2020 was so intense that even the top branches of many trees burned and their ability to photosynthesize (光合作用) went up in smoke along with their pine needles. Trees photosynthesize to create sugars and other carbohydrates (碳水化合物), which provide the energy they need to grow and repair tissue. Trees do store some of this energy, which they can call on during a drought or after a fire. Although the redwoods have sprouted (长出) new growth, Peltier and other forest experts wonder how the trees will cope with far less energy from photosynthesis, given that it will be years before they grow as many needles as they had before the fire. “They’re alive, but I would be a little concerned for them in the future.”

1. What’s special about this big fire for coastal redwood forests in 2020?

A．It burnt the top of the trees.	B．It was very close to the last fire.
C．It resisted burning effectively.	D．It caused relatively minor damage.

2. Why did redwoods survive in the big fire?

A．Sugars protected their barks.	B．Energy reserves promoted the growth of buds.
C．They got used to hot climate.	D．They took in much carbon to resist fire.

3. What does the underlined word “infernos” in the third paragraph mean?

A．Unpredictable disasters.	B．Changeable climate.
C．Terrible environment.	D．Uncontrollable fires.

4. Why does Peltier worry about the survival of redwoods?

A．Their tissues can’t be repaired.	B．They can’t save energy anymore.
C．Their energy saved is not sufficient.	D．They grow too slowly.

9 . Cork is a light brown material harvested from the cork oak tree. Cork is lightweight, strong and resistant to water.     1     For thousands of years, people have used pieces of cork as closures for bottles because cork is made of small cells filled with air. It is said that no technology has been able to copy this unusual material exactly.

The cork oak tree is native to the western Mediterranean coast of Europe.     2     In fact, Portugal produces more than half of the world’s cork supply. Cork oak trees have to be at least twenty-five years old before they are ready for harvest.     3     Cork is gathered by skillfully cutting off the outer layer of the tree with special knives. The harvest weakens the tree temporarily, but it soon starts to grow a new layer of bark. Next, the cork harvest is set out in the open for six months. Then, the cork is boiled in order to clean it and make it softer.     4    

Because cork oak trees are not killed during harvest, they can live for as long as 200 years. Also, used cork products can be recycled and used again. This makes cork a valuable renewable resource.     5    Wine makers say cork stoppers in their bottles let the wine be aged and improve over time. But now some wine producers are changing to plastic or metal closures. Some environmentalists worry that if cork starts to lose its value, the cork oak forests in Europe will no longer be protected.

A．After drying, the cork is ready to be cut.

B．Harvests only happen once every nine years.

C．Cork has even found a use in making rockets.

D．It is best known for keeping liquids from spilling.

E．Cork can be shined and used to cover floors and walls.

F．The largest cork oak forests in the world are in Portugal.

G．The wine industry has been a major supporter of cork production.

10 . 听下面一段较长对话，回答以下小题。
1. What’s the size of the redwood forest in Muir Woods National Monument?

A．240 acres.

B．319 acres.

C．559 acres.

2. How old are the redwood trees in Muir Woods?

A．Less than 400 years old.

B．400 to 800 years old.

C．More than 1 ,000 years old.

3. What kind of climate do the redwood trees like?

A．Dry and sunny.

B．Wet and rainy.

C．Wet and foggy.

4. Which city is the redwood forest near?

A．New York.

B．San Francisco.

C．Los Angeles.