1 . 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

2 . Why did the woman’s plants die according to the man?

A．From not enough water.

B．From not enough sun.

C．From not enough plant food.

3 . 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.

4 . What kind of plants does the neighbor have according to the man?

A．Weeds.

B．Wild flowers.

C．Flowers from store.

5 . Scientists have been experimenting with playing sounds to plants since at least the 1960s, during which time they have been exposed to everything from Beethoven to Michael Jackson. Over the years, evidence that this sort of thing can have an effect has been growing. One paper, published in 2018, claimed that an Asian shrub known as the telegraph plant grew substantially larger leaves when exposed to 56 days of Buddhist music — but not if it was exposed to Western pop music or silence. Another, published last year, found that marigolds and sage plants exposed to the noise of traffic from a busy motorway suffered growth difficulty.

Plants have been evolving (进化) alongside the insects that eat them for hundreds of millions of years. With that in mind, Heidi Appel, a botanist now at the University of Houston, and Reginald Cocroft, a biologist at the University of Missouri, wondered if plants might be sensitive to the sounds made by the animals with which they most often interact. They recorded the vibrations made by certain species of caterpillars (毛毛虫) as they chewed on leaves. These vibrations are not powerful enough to produce sound waves in the air. But they are able to travel across leaves and branches, and even to neighbouring plants if their leaves touch.

They then exposed tobacco plant — the plant biologist’s version of the laboratory mouse — to the recorded vibrations while no caterpillars were actually present. Later, they put real caterpillars on the plants to see if exposure had led them to prepare for an insect attack. The results were striking. Leaves that had been exposed had significantly higher levels of defensive chemicals, making them much harder for the caterpillars to eat. Leaves that had not been exposed to vibrations showed no such response. Other sorts of vibration — caused by the wind, for instance, or other insects that do not eat leaves — had no effect.

“Now speakers with the right audio files are more often being used to warn crops to act when insects are detected but not yet widespread,” says Dr. Cocroft. “Unlike chemical pesticides, sound waves leave no dangerous chemicals.”

1. What can we learn about plants from the first paragraph?

A．They may enjoy Western music.	B．They can’t stand Buddhist music.
C．They can react to different sounds.	D．They can make different sounds.

2. What’s the basis for Appel and Cocroft’s research?

A．Plants can make a cry for help.	B．Plants evolve alongside insects.
C．Plants are sensitive to the sounds.	D．Plants have been studied for years.

3. What can we infer about plants from Paragraph 3?

A．They can recongnize harmful vibrations.	B．They look like laboratory mice.
C．They can threaten the caterpillars.	D．They can release poisonous chemicals.

4. What does the last paragraph mainly talk about?

A．Disadvantages of chemical pesticides.	B．Application of the experimental results.
C．Interaction between plants and insects.	D．Warning system of widespread insects.

6 . In 1986, when he was only a prince. King Charles told a television interviewer that it was important to talk to plants. He was widely laughed at. But his wisdom seems to have been ahead of its time, for there is now plenty of evidence that plants can detect (察觉) sound, react to it, and even perhaps produce it.

Scientists have been experimenting with playing sounds to plants since at least the 1960s, during which time they have been exposed to everything from Beethoven to Michael Jackson. Over the years, evidence that this sort of thing can have an effect has been growing. One paper, published in 2018, announced that an Asian plant grew much larger leaves when exposed to 56 days of Buddhist chants — but not if it was exposed to Western pop music, or silence. Another, published last year, found that plants exposed to the noise of traffic from a busy motorway suffered slow growth, and produced a range of stress compounds (成分).

Another research reports that certain frequencies (频率), played in some environments like greenhouses, can affect seed growth and even improve crop production. And plants can make noises, too. Earlier this year a group of researchers at Tel Aviv University published an article in Cell Press, reporting that several plants gave out different noises in response to different stresses — although not at the sorts of frequencies that humans can hear. Humans can only hear frequencies of up to 16 kilohertz. Scientists discovered sounds given out by plants were up to 250 kilohertz.

If all that sounds strange, perhaps it should not. After all, sound carries useful information.

From an evolutionary point of view, there is no reason to expect that information to be applied only by animals.

1. What was most people’s attitude to Charles’ opinion?

A．Unclear.

B．Positive.

C．Cautious.

D．Negative.

2. What can we learn from paragraph 2?

A．Different sounds have different effects on plants.

B．Buddhist chants don’t make a difference to plants.

C．Western pop music does good to plants’ growth.

D．The noise of traffic produces stress compounds.

3. Why can’t humans hear sounds given out by plants?

A．The sounds are strange.	B．The plants grow in greenhouses.
C．The plants are under great stress.	D．The sounds are at high frequencies.

4. What’s the main idea of the text?

A．It’s the important to talk to plants.

B．Sounds make a difference to plants.

C．Plants can discover and even make sound.

D．Humans can’t hear sounds produced by plants.

7 . Scientists have known for years that plants respond to sounds around them. For example, flowers make sweeter nectar (花蜜) to the sound of buzzing bees. But now scientists in Israel have shown that plants also seem to be doing some “talking”.

Professor Lilach Hadany and her team at Tel Aviv University set up microphones to record tomato and tobacco plants under different conditions. Their recordings showed that the plants made ultrasonic (超声波的) sounds.

When the researchers adjusted their recordings so that humans could hear them, they heard sharp clicking noises. Plants clicked hardly at all when they had enough water. But as their soil got drier, they clicked more and more. When scientists cut off a stem (茎) from the plants, the plants also clicked more. But the clicking wasn’t the same as when the plants needed water.

It’s not clear how the plants make the sounds and whether the plants are making the sounds on purpose. But the plants are definitely making noises, and creating much more noises when they’re stressed (not enough water, stem cut off) than when they’re not.

The researchers trained an Artificial Intelligence (AI) system to identify the different kinds of clicking sounds. The system was able to tell the difference between plants that needed water and plants with cuts about 70% of the time. The result suggests that researchers may one day be able to use a plant’s sounds to figure out when it is having trouble, and what trouble it is having. That could be very helpful to farmers.

The new discovery raises many more questions. One important question is: Do plants make sounds to communicate with each other? Other research has shown that plants do seem to communicate in some ways. Plants being attacked by insects send chemicals into the air. Soon, nearby plants (that haven’t been attacked yet) start to make other chemicals that don’t taste good to insects. It’s possible that the ultrasonic sounds could work in a similar way.

1. What do the researchers find in their recordings?

A．Plants’ stems click less when they are cut off.

B．Plants click harder if they have enough water.

C．Plants make more noises when they are thirsty.

D．Flowers make sweeter nectar to the sound of bees.

2. What can we learn about the plants from paragraph 4?

A．There are still some unknown issues.

B．Not all of them are able to make sounds.

C．There are ultrasonic sounds around them.

D．They make less noises when they’re stressed.

3. What is the purpose of the AI system created by the researchers?

A．To help farmers drive away insects.

B．To identify people who are in trouble.

C．To show the growing process of plants.

D．To distinguish types of clicking sounds.

4. What might the author continue talking about?

A．Methods for plants to protect themselves.

B．Other questions raised by the new finding.

C．When plants communicate with each other.

D．Under what conditions plants attract insects.

8 . On the streets of Manhattan and Washington, D. C., in neighborhoods in Seoul and parks in Paris, ginkgo (银杏) trees are losing their leaves in reaction to the first gust of cold winter air. This leaf drop, gradual at first, and then sudden, carpets streets with golden, fan-shaped leaves. Scientists are documenting evidence of the event happening later and later, a possible indication of climate change. But the story of ginkgos is not the familiar one of human carelessness with nature.

Thanks to fossils found in North Dakota, scientists found a ginkgo has genetically similar ancestors dating back 170 million years to the Jurassic Period. “It almost went extinct. Then humans rescued it and spread it around the world. It’s such a great evolutionary (进化) and cultural story,” says Peter Crane, a ginkgo expert.

One theory for the decline of the ginkgo species began 130 million years ago, when flowering plants began spreading. They grew faster and attracted more pollinators (传粉者) than ginkgos. “It’s possible that ginkgos were elbowed out of the way,” says Crane. Already competing to survive, ginkgos began to disappear during a time of global cooling that began around 66 million years ago. By the time the last ice age ended 11,000 years ago, the remaining survivors were found in China.

Ginkgo trees are smelly. “My guess is that they were eaten by animals that liked smelly things. They then passed through their body and grew.” Crane says. Those same seeds may have helped ginkgo find favor with humans 1,000 years ago. Once cleaned of their outer layer, ginkgo seeds are safe to eat. It’s then, when the trees had long since disappeared elsewhere, that people in China may have begun planting them and eating their seeds. Then gradually ginkgos spread across the world. Now it’s seemingly naturally resistant to insects and high levels of air pollution.

Crane isn’t worried about its future, though: The popularity of the species will help it survive. “Though its status in the wild may be difficult to access, it’s a plant that’s unlikely to ever go extinct,” he says.

1. What may have caused the further delay of ginkgo’s leaf drop?

A．The colder weather in winter.

B．The protection from city councils.

C．The global warming phenomenon.

D．The careless interaction with humans.

2. What does paragraph 3 mainly talk about?

A．The reasons why ginkgos almost died out.

B．The advantages of ginkgos over other plants.

C．The theories of experts for multiplying ginkgos.

D．The competition between various flowering plants.

3. What might have contributed to ginkgos’ survival?

A．Their eatable seeds.	B．Their unpleasant smell.
C．The natural evolution.	D．The careful planting.

4. How does Crane feel about ginkgos’ future?

A．Worried.

B．Optimistic.

C．Uncertain.

D．Hopeless.

9 . Keeping a bit of the outdoors inside is nothing new, but houseplant collections have become a popular social media trend — which means that more people than ever are discovering the comfort and beauty that caring for plants brings.

    1     Exposure to greenery, whether you have indoor plants, take walks outside or tend to a garden, has been found to have multiple mental-health benefits, such as lowering stress, decreasing feelings of depression, increasing sociability, restoring focus, improving cognitive performance, improving mood and increasing self-esteem.

“One study showed that patients at a hospital who had plants in their room reported less pain, lower blood pressure, less fatigue and less anxiety than patients without plants in their rooms,” says Jenny Seham, a New York-based psychologist. She explains: “Cortisol, the stress hormone, has been shown to lower with plant interaction, reducing fatigue, irritability (易怒) and blood pressure.”

Research has also shown that having plants and gardening increase productivity and levels of serotonin, the neurotransmitter responsible for lifting our mood.     2     And it is also opposed to dwelling on the past or worrying about the future.

Before you fill your space with greenery, consider how you’ll interact with your plants.     3     Can you care for them daily?

If you have a small space or aren’t sure how much time you’re willing to invest in “plant parenting.” Start slow. “    4     It can engage you by its smell or colour, creating a positive mood response with every interaction,” says Seham.

A．For instance, is there enough space for plants in areas where you spend a lot of time?

B．Half the fun of gardening is that you never know exactly what’s going to come up.

C．It’s a feel-good hobby that’s supported by science.

D．While indoor gardening can boost your feelings of wellbeing, help reduce stress and promote relaxation, it’s not, of course, a substitute for a trained mental health professional.

E．The theory is that plant care helps us focus on the present moment and provides a feeling of accomplishment.

F．Just one plant can make a difference.

10 . Under a midday summer sun in California’s Sacramento Valley, rice farmer Peter Rystrom walks across a dusty and bare plot of land, dry soil crunching (碎裂) beneath each step. In a typical year, he’d be walking across green rice fields in inches of water. But today the soil is dry and baking in the 35℃ heat. It hasn’t rained for 4 weeks in a row.

“Climate change is expected to worsen the state’s extreme swings in rainfall,” researchers reported in Nature Climate Change in 2018. Low water levels in rivers have forced farmers like Rystrom, whose family has been growing rice on this land for four generations, to reduce their water use.

“If we lose our rice crops, we have to deal with severe food crisis. Climate change is already threatening rice-growing regions around the world. This is not a future problem. This is happening now,” says plant geneticist Pamela Ronald of the University of California, Davis, who identifies genes in rice that help the plant stand up to dryness, disease, flood, etc.

To save and even boost production, rice growers, engineers and researchers have turned to water-saving irrigation (灌溉) routines. Building canal systems and reservoirs (水库) can help farmers dampen their fields. But for some, the solution to rice’s climate-related problems lies in enhancing the plant itself. They hold that establishing rice gene banks that store hundreds of thousands of rice varieties ready to be bred into new, dryness-tolerant varieties is more practical and effective. Solutions may be hidden in the DNA of those older breeds.

Three decades have passed since its initial development, and some researchers are looking beyond the genetic variability preserved in rice gene banks, searching instead for useful genes from other species, including plants and bacteria. But picking genes from one species and putting them into another, or genetic recombination, remains debatable. The most famous example of genetically changed rice is Golden Rice (GR). “Looking ahead, it will be crucial for countries to embrace GR rice. But it will take time,” says Ismail, principal scientist at IRRI,

1. What problem does Rystrom have to deal with?

A．Thirst.

B．Drought.

C．Hot sun.

D．Dusty weather.

2. What can be inferred from Para. 3?

A．Downtrend of rice-growing areas is severe now.

B．Climate change is a threatening factor in the future.

C．Humans will face starvation if crop failure happens.

D．Food crisis is a common occurrence around the world.

3. What’s the purpose of setting up gene banks?

A．To store as many seeds as possible.	B．To cultivate climate-adapted varieties.
C．To improve the efficiency of breeding.	D．To show the technology of gene mapping.

4. What’s Ismail’s opinion about GR?

A．Favourable.

B．Impractical.

C．Disapproving.

D．Insecure.