1 . 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.

2 . Common water plant could provide a green energy source. Scientists have figured out how to get large amounts of oil from duckweed, one of nature’s fastest-growing water plants. Transferring such plant oil into biodiesel (生物柴油) for transportation and heating could be a big part of a more sustainable future.

For a new study, researchers genetically engineered duckweed plants to produce seven times more oil per acre than soybeans. John Shanklin, a biochemist says further research could double the engineered duckweed’s oil output in the next few years.

Unlike fossil fuels, which form underground, biofuels can be refreshed faster than they are used. Fuels made from new and used vegetable oils, animal fat and seaweed can have a lower carbon footprint than fossil fuels do, but there has been a recent negative view against them. This is partly because so many crops now go into energy production rather than food; biofuels take up more than 100 million acres of the world’s agricultural land.

Duckweed, common on every continent but Antarctica, is among the world’s most productive plants, and the researchers suggest it could be a game-changing renewable energy source for three key reasons. First, it grows readily in water, so it wouldn’t compete with food crops for agricultural land. Second, duckweed can grow fast in agricultural pollution released into the water. Third, Shanklin and his team found a way to avoid a major biotechnological barrier: For the new study, Shanklin says, the researchers added an oil-producing gene, “turning it on like a light switch”by introducing a particular molecule (分子) only when the plant had finished growing. Shanklin says, “If it replicates (复制) in other species-and there’s no reason to think that it would not — this can solve one of our biggest issues, which is how we can make more oil in more plants without negatively affecting growth.”

To expand production to industrial levels, scientists will need to design and produce large-scale bases for growing engineered plants and obtaining oil — a challenge, Shanklin says, because duckweed is a non-mainstream crop without much existing infrastructure (基础设施).

1. What can people get from duckweed firsthand?

A．Plant oil.	B．Stable biodiesel.
C．Sustainable water.	D．Natural heat.

2. What does paragraph 4 mainly convey?

A．Options for renewable energy.

B．Reasons for engineering genes.

C．The potential of revolutionary energy source.

D．The approach to avoiding agricultural pollution.

3. What is the decisive factor to mass-produce the plant?

A．Industrial levels.	B．Unique design.
C．Academic research.	D．Basic facilities.

4. What would be the best title for the text?

A．Duckweed Power	B．Duckweed Production
C．Genetic Engineering	D．Genetic Testing

3 . When gardeners grow varieties of plants in their beautiful gardens, they are happy to see beneficial insects like bees and butterflies surrounding the flowers. But as they take a closer look, they may find some plants are covered in black dots and filled with harmful insects or pests. Some gardeners may immediately reach for chemicals.     1     Although it may stop the insect problem, it will also threaten bees and butterflies which help the plants reproduce.

If you are wise gardeners, you should first take preventive measures to control the harmful insects.     2     Only when there are too many harmful insects, should pest control be considered. The first defense should always be the safest method available.

Prevention

As a rule, prevention is the best treatment. Inspect plants closely, including their leaves, before buying them from the store.     3    

When planting, space plants out to permit them to grow to their full size. Plants too close together can breed harmful organisms, like bacteria.

    4     They invite pests if permitted to remain on the ground. When you do see pests, wash them away. Use rubbing alcohol to remove some insects, or pick them off the plants.

Pesticides

If you decide a pesticide is necessary, choose it carefully and follow the directions and warnings on the product. Avoid using pesticides in extreme heat, on windy days, or when the plants are wet.     5     At the time, beneficial insects are inactive. You can consider removing flowers from the plants to lessen the risk that beneficial insects will come in contact with the pesticides.

A．But this is not wise.

B．In most cases, chemicals don’t help.

C．Treat the plants early in the morning or at night.

D．Also do remember the plants need nutrition and care.

E．Keep your garden free of fallen leaves, fruits and other wastes.

F．Do not bring any plants home that show signs of disease or pests.

G．The process starts with the idea that having some pests is acceptable.

4 . To adapt to climate change, some flowers are darkening their color to protect themselves from the sun’s radiation, new research shows.

The study suggests that over the past 75 years, the ultraviolet (UV) pigments (紫外线色素) in flowers have increased in response to rising temperatures and a thinning ozone layer (臭氧层). The flowers won’t look any different to humans, but insects consider the higher levels of UV pigments as a darker color, which could be confusing when they try to find out colorful flowers to land on.

The UV-absorbing pigments in flowers work like sunscreen and protect sensitive cells from harmful radiation, Matthew Koski, a plant ecologist at Clemson University, says. He and his team hoped to determine if changes in pigments were a result of environmental change — and if so, what are the plants responding to?

The team collected dried, pressed plants across North America, Australia, and Europe. In total, they studied 1,238 samples from 42 different species dating back to 1941. Then, using a UV-sensitive camera, they photographed flower petals from each species to see how the pigment level changed over time. Next, they paired the photographs with historic local temperature and ozone level data from the time the plant was picked.

The researchers found that the changes in pigments differ by species, a result of the flower’s structure. Flowers with open, exposed pollen (花粉) had more UV-absorbing pigments when ozone levels were low and radiation was high. But flowers with pollen surrounded by the petal responded to temperature, not ozone levels.

As climate change continues to intensify, these changes in flowers’ color can affect plant-insect interactions. When the whole flowers get darker, insects might miss the flowers entirely. “This has a negative influence on plant reproduction.” Koski says.

1. What is the cause of flowers’ color changing according to the research?

A．The impact of climate crisis.	B．The loss of natural habitats.
C．The harm of nuclear radiation.	D．The thickening of ozone layer.

2. What arc Koski’s findings based on?

A．Photographs of flowers from different species.

B．Analysis of how levels of UV pigments change over time.

C．Collection of abundant samples from various species.

D．Historic local temperature and ozone level database.

3. What can we learn about the change in pigments?

A．It exists in flowers with exposed pollen only.

B．It responds to temperature and sea levels.

C．It remains the same regardless of species.

D．It varies depending on the flower’s structure.

4. What is Koski’s attitude towards the change in flowers’ color?

A．Concerned.

B．Indifferent.

C．Unclear.

D．Optimistic.

5 . Seagrass meadows(海草床) are wonder plants growing beneath the sea. They feed and shelter sea life and are masterful at storing carbon. Thanks to the assistance of tiger sharks, a huge seagrass meadow in the Bahamas Banks was recently discovered, offering the world a tool to fight climate change.

Seagrass has usually been detected by Earth-orbiting satellites that identify darker patches in the blue water. In this study, tiger sharks were selected as research tools due to their highly consistent associations with seagrass ecosystems. They spend 70% of their time in seagrass meadows. The team equipped eight tiger sharks with satellite tags (电子跟踪器), seven sharks with camera tags, and used a 360-degree camera on a shark for the first time ever.

The data researchers collected was astonishing. The world’s largest seagrass ecosystem, measuring at least 66,900 square kilometers, has been discovered. This reflects a 41% increase from previous estimates of global seagrass. Seagrass can capture (捕获) huge quantities of carbon by photosynthesis (光合作用) and stores it on the seafloor. In terms of climate change, this is excellent news; seagrass is 35 times faster a removing carbon than tropical rainforests. When referred to global seagrass carbon stock estimates, the study indicates that seagrass in the Bahamas may contain 19.2% to 26.3% of all the carbon stored in seagrass meadows on Earth.

Yet seagrass meadows are rapidly disappearing, with over 92% of meadows in the UK gone, according to the World Wildlife Fund. Scientists are collecting seeds and trying to grow new seagrass meadows through restoration projects. This new discovery offers optimism and proves the importance of the ocean for healing.

The sharks led us to the seagrass ecosystem in the Bahamas, which we now know is likely the most significant blue carbon sink(蓝色碳汇) on the planet. What this discovery shows us is that ocean exploration and research are essential for a healthy future. The untapped potential of the ocean is limitless. These meadows can be protected and can be replicated (复制,仿制), offering hope for climate change around the globe.

1. Why were tiger sharks chosen as research tools?

A．They are more flexible than other sea animals.

B．They can quickly adjust themselves to the deep sea.

C．They have a strong connection with seagrass ecosystems.

D．They can be easily equipped with experimental devices.

2. What are the numbers in paragraph 3 mainly about?

A．The decline of global seagrass meadows.

B．The impact of climate change on sea life.

C．The rapid increase in the amount of carbon on Earth.

D．The potential value of the world’s largest seagrass ecosystem.

3. What are scientists doing to protect seagrass?

A．Planting more seagrass meadows.

B．Developing new technology to collect seeds.

C．Mapping the distribution of seagrass meadows.

D．Encouraging people to join in restoration projects.

4. Which could be the best title for the text?

A．The New Way of Removing Carbon

B．The Significance of Ocean Exploration

C．A New Discovery: World’s Largest Seagrass Meadow

D．Tiger Sharks: Scientists’ Essential Helper to Study Climate

6 . 阅读下面短文, 在空白处填入1个适当的单词或括号内单词的正确形式。

Yunnan is the hometown of tea. It provides the ideal climate and the ecological environment for large-leaf tea trees, which are located in the     1     (region) along the Lancang River. Thousands of years ago, they formed those ancient tea plantations,     2     are the best gift that nature has grated us.

    3     (preserve) the ancient tea trees, Southwest Chinn’s Yunnan Province has passed a protection regulation recently,     4     (clarify) that wild and cultivated ten plants aged over 100 wars should be better protected in the province. The new regulation, which will come into force starting from March 1, 2023,    5    (prohibit) six kinds of behaviors that harm ancient tea plants and their growing environment. Unauthorized cutting and transplantation of ancient tea trees, carving tree branches, digging the roots,     6    damaging the ancient lea trees are all banned.

Other     7     (legal) practices include using harmful chemical herbicides, releasing waste gas and water, as well as dumping and throwing waste     8     (casual) within the protection range of the trees, according to the regulation.

Yunnan has diverse resources of tea trees. The regulation also advocates proper research and     9    (apply) of Yunnan’s resources of ancient tea trees, raising varieties     10    new tea trees of good quality, as well as the establishment of relevant industrial chains.

7 . 阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

Hua Weiguang,     1     retired teacher from Tongliao, Inner Mongolia Autonomous Region, is a photography enthusiast.

A decade ago, the arrival of tree planters     2     (catch) Hua’s attention and the photos of the tree planters     3     (take) by Hua are evidence of the     4     (remark) transformation of the land. In those photos, hats, scarves and goggles, for the workers fighting desertification, are basic necessities to protect them     5     the wind and sand. There was no way to avoid the brutal summer heat in the land so the workers had to lie down on the ground or curl up in the narrow shade of their cars to cool off. And they also had to eat their lunch amid the blowing sands, taking in the small pieces of sand with their food.

“    6     we don’t fool the tree, it won’t fool you. You take it     7     (serious), and then it behaves in the same way to you. You put efforts to make it live, and the tree lives up to your     8     (expect),” the planters say.

China’s forest resources have increased by over 70 million hectares in the past decade,     9     (rank) first in the world. One tree after another, a green Great Wall has been built. Brush by brush, a green field     10     (paint) over the yellow sandy land up to now.

8 . It turns out that sunflowers are more than just a pretty face: the ultraviolet (紫外线的) colours of their flowers not only attract pollinators (传粉者), but also help the plant regulate water loss, according to new research.

The yellow sunflower is a familiar sight, but it’s hiding something from the human eye — an ultraviolet bullseye (靶心) pattern, invisible to humans but not to most insects including bees. These bullseye patterns have long been known to improve the attractiveness of flowers to pollinators by increasing their visibility.

“Unexpectedly, we noticed that sunflowers growing in drier climates have flowers with larger ultraviolet bullseyes, and found that those flowers are able to keep water more efficiently. This suggests that these larger ultraviolet bullseyes help plants adapt to these drier environments,” says Dr. Marco Todesco.

Dr. Todesco and his colleagues grew almost 2,000 wild sunflowers of two species at the university in 2016 and 2019. They measured the sunflowers’ ultraviolet patterns, and analyzed the plants’ genes, and found that wild sunflowers from different parts of North America had ultraviolet bullseyes of very different sizes.

Larger floral ultraviolet patterns that have more of these compounds could help reduce the amount of water loss from a sunflower in environments with lower humidity (湿度), preventing too much water loss. In humid, hot environments, smaller ultraviolet patterns would promote the water loss, keeping the plant cool and avoiding overheating.

Sunflowers are planted for various purposes, including sunflower oil production, a roughly $20 billion industry in 2020. This research could help add to knowledge about how to attract pollinators, potentially increasing crop yields, says Dr. Todesco. “This work also helps us understand how sunflowers, and potentially other plants, better adapt to different areas or temperatures, which could be important in a warming climate.”

1. What do we know about sunflowers?

A．They don’t need pollinators.

B．Their flowers have special functions.

C．Their flowers can drive the insects away.

D．They can be grown in extremely cold areas.

2. What did Dr. Todesco and his colleagues do?

A．They analyzed 2000 kinds of sunflowers.

B．They planted sunflowers to carry out research.

C．They travelled to different parts of South America.

D．They helped people in North America plant sunflowers.

3. What is Dr. Todesco’s attitude to the research on sunflowers?

A．Positive.	B．Doubtful.
C．Negative.	D．Critical.

4. What can be the best title for the text?

A．A Hidden Function of Flowers of Sunflowers

B．Researchers Found a New Species of Sunflower

C．Sunflowers Can Change the Colours of Sunshine

D．Ultraviolet Bullseye Patterns Attract More Insects

9 . 阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

Giant Amazonian lily pads(睡莲叶) are the world’s largest and strongest floating plants and the giant Amazonian water lily has long fascinated scientists, architects and artists for    1    (it) beauty and sheer size. Yet how the lily’s leaves are able to grow as large as 10 feet across, strong enough to support the    2    (weigh) of a small child,    3    (remain) a mystery—till now. “    4    we showed through our experiments and modeling was that these leaves are uniquely strong and have great opportunities    5    (enable) them to grow really big,” says Thorogood, from a team of British and French scientists. In fact, the giant lily    6    (discover) by British explorers in South America in 1801 and symbolized the British Empire. But it became more than    7    symbol as botanists repeatedly attempted to grow it at home. The British gardener and architect Joseph Paxton was the first to    8     (success) grow the giant water lily. It inspired his design of the Crystal Palace, a London landmark of cast iron and glass that was built for the Great Exhibition of 1851. “Nature was the engineer,” Paxton said. “Nature has provided the leaf    9    special structures and supports that I,    10    (borrow) from it, have adopted in this building.”

10 . About 17 years ago, I became allergic to Delhi's air. My doctors told me that my lung function had gone down to 70 percent. My doctor told me that there were three plants, with which I could grow all the fresh air indoors to keep me healthy.

The three plants are Areca palm, Mother-in-law's Tongue and money plant. Areca palm is a plant which removes CO₂ and turns it into oxygen. We need four shoulder-high plants every person. The second plant is Mother-in-law's Tongue. It is called a bedroom plant because it turns CO, into oxygen at night. And we need six to eight waist-high plants every person. The third plant is money plant, and it preferably grows in hydroponics. This particular plant removes some harmful chemicals.

My team and I have tried these plants at our own building in Delhi, which is a 50,000-square-feet, 20-yearold building. And it has close to 1,200 such plants for 300 families. Our studies have found that there is a 42 percent probability of one's blood oxygen going up by one percent if one stays indoors in this building for 10 hours. Our experience also points to an amazing reduction in energy requirements in the building by an outstanding 15 percent. The government has published a study to show that this is the healthiest building in Delhi. And the study has also shown that, compared to other buildings, there is a reduced incidence of headaches by 24 percent.

In my opinion, these studies above are also important for the environment because the world’s energy requirements are expected to grow by 30 percent in the next decade. 40 percent of the world's energy is taken up by buildings currently, and 60 percent of the world's population will be living in buildings in cities with a population of over one million in the next 15 years. And there is a growing preference for living and working in air-conditioned places.

1. What is the function of the first paragraph?

A．To show the results of growing plants.	B．To give the reason for the author's studies.
C．To introduce the author's life.	D．To praise the author's doctor.

2. Which of the following can remove harmful chemicals according to the text?

A．CO2.

B．Oxygen.

C．Money plant.

D．Mother-in-law's Tongue.

3. What can we learn from the government's study?

A．The building with the three plants is the healthiest in Delhi

B．The possibility of headaches reduces by 40 percent.

C．The energy requirements in the building drop by 42 percent.

D．People can stay in the building for only 10 hours.

4. What does the author think of these studies?

A．Complex.

B．Boring.

C．Meaningful.

D．Useless.