1 . The San Francisco-based company, called Living Carbon, has created poplar (杨树) trees that are genetically engineered (改变基因结构) to grow larger and suck up more carbon dioxide from the atmosphere than standard trees do. In February, workers planted rows of these poplars in southern Georgia. The company intends to plant 4 to 5 millions trees by the middle of next year, which they say will help with the worsening climate crisis.
When plants photosynthesize (进行光合作用), they convert carbon into sugar and nutrients that are eventually consumed by all living organisms. But they also produce a harmful byproduct, which must be broken down during the energy-intensive process of photorespiration (光呼吸), said Yumin Tao, the company’s vice president of biotechnology.
“This is not only wastes energy but also loses much fixed carbon in the form of CO2, which gets released into the air again,” Tao added. “It’s a wasteful process many plants do.” Living Carbon has reduced photorespiration in its poplars, instead channeling the energy into growth, he says.
The trees have three genes inserted to achieve this, including one from squash and one from green algae. But the company has yet to show its modified trees can capture more carbon in a real — world setting. Its only publicly available data comes from a study in a greenhouse that lasted for only a few months and has yet to be peer reviewed. “Their claims seen bold based on very limited real-world data,” says Andrew Newhouse, a conservation biologist at the SUNY College of Environmental Science and Forestry.
Still, the study reported the modified poplars grew as much as 53% larger in five months compared to the unmodified ones, capturing 27% more carbon dioxide. Now, the company hopes its other field trials in locations like Oregon and Pennsylvania will show similar successes. It’s currently focused on planting on private lands, where fewer roadblocks exist.
“We specially focus on land where trees otherwise wouldn’t be planted, like abandoned mine lands-areas where there isn’t an existing, rich ecosystem that’s allowing for a large amount of carbon removal right now,” says Maddie Hall, Living Carbon’s CEO.
1. Why does the company want to plant genetically modified poplars?| A．To help with the worsening climate crisis. |
| B．To better study them to gain more accurate data. |
| C．To replace ordinary poplars with genetically modified poplars. |
| D．To find suitable places for genetically modified poplars to grow. |
| A．Disapproving. | B．Ambiguous. | C．Skeptical. | D．Supportive. |
| A．They are very resistant to carbon. | B．They have a growth advantage. |
| C．They have two genes inserted. | D．They photosynthesize even faster. |
| A．A Company Is Trying to Engineer Trees Genetically |
| B．Poplar Trees Might Be Planted All Around the World |
| C．Genetically Modified Trees Are Taking Root to capture Carbon |
| D．Research Is Being Conducted to Use Trees to Remove CO2 |
1. What makes potted roses easier to plant?
| A．Lower nutrition requirement. |
| B．Stronger cold resistance. |
| C．Better root development. |
| A．They need less soil. |
| B．They are easier to transport. |
| C．Their planting time is fixed. |
| A．Damp condition. | B．Heavy sunshine. | C．Continuous watering. |
| A．Types of roses. | B．Ways of rose packing. | C．Tips on rose growing. |
3 . 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. |
| 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. |
| 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. |
| A．Favourable. | B．Impractical. | C．Disapproving. | D．Insecure. |
Camellias (山茶花) are available in a great range
In the 1960s, Chinese scientists announced their discovery of the golden camellias. It was an
Unfortunately, in the past, golden camellias were cut down in large numbers because
Year after year, the Huang brothers spent much time working
5 . According to a new research, flowers are listening. Researchers found that plants can actually hear the sound of passing bees and produce sweeter nectar (花蜜) to attract them.The team discovered that within minutes of sensing the sound waves of bee wings, the concentration of the sugar in the plant’s nectar was increased by 20 percent.
Also, flowers can remove the wind noise coming from the background. These capabilities can give plant advantages for their spreading pollen (花粉). The researchers showed that plants can rapidly respond to pollinator (传粉者) sounds.
Before the experiments, researchers made the assumption that plants can pick up the sound waves and that this might be part of the reason why many plants’ flowers are bowl-shaped, to better trap the sounds. However, after performing various experiments on 650evening primrose flowers, the nectar production was measured both in silence and at three different frequency levels. Also, a recording of the noise made by bees was played. In just three minutes, the nectar changes have been noticed and it has been release d that silence and the high and mid-frequency sounds had no effect. The team has also performed an experiment with plants that had some flower petals removed and no change in nectar production was noted. Hence, it is proved that the flowers petals have the job of the ears.
The more sweet nectar comes out, the more will be the chances for pollen to be spread and also makes it more likely that the insects will return to flowers of the same species in the future. However, more work needs to be carried out on how the sounds are turned into a trigger for sweeter nectar production.
1. Why do plants produce sweeter nectar?.| A．To attract bees. | B．To be more beautiful. |
| C．To avoid enemies. | D．To drive insects away. |
| A．Why researchers did the experiments. | B．How researchers made the discovery. |
| C．What use can be made of the discovery. | D．What the importance of the discovery is. |
| A．High sound increases sugar in the nectar. |
| B．Many plants’ flowers are bowl-shaped to catch light. |
| C．Flowers petals have no effect on nectar production. |
| D．More research is needed to fully understand the process. |
| A．A diary. | B．A novel. | C．A newspaper. | D．A notebook. |
6 . A Fish and Wildlife Service proposal would protect the whitebark pine as an endangered species. Whitebark pines can live for up to 1,000 years and grow at elevations (海拔) as high as 12,000 feet. Environmentalists had requested the government in 1991 and again in 2008 to protect the trees. A nonnative fungus (真菌) has been killing whitebark pines for a century. More recently, the trees have proved vulnerable (易受伤的) to tiny insects that have killed large areas of forest.
The whitebark pines have almost disappeared in some areas, including the eastern edge of Yellowstone National Park, where they are a source of food for threatened grizzly bears (灰熊). This makes the government’s declaration of the Yellowstone area’s grizzly bears as a restored species a lie.
After being blamed for not taking steps to protect the trees, wildlife officials in 2011 admitted that whitebark pines needed protection, but they didn’t act rapidly, saying other species faced more immediate threats.
A lawyer for the Natural Resources Defense Council, which made the formal request for protection in 2008, expressed his disappointment that it took so long but said the proposal was still worth celebrating.
The government’s proposal described the threats to the trees as immediate and said the whitebark pines were one of many plants expected to be harmed as climate change moves faster than they can adapt. “Whitebark pines survive at high elevations already, so there is little remaining habitat in many areas for the species to move to higher elevations in response to warmer temperatures,” Fish and Wildlife Service officials wrote.
Government officials are working with researchers and private groups on plans to gather seed from trees, grow them in greenhouses and then plant them back on the landscape, according to Fish and Wildlife Service biologist Amy Nicholas. A proposal of that nationwide restoration is expected by the end of this year. “We do have options to restore this species,” Nicholas said.
1. What do we know about whitebark pines?| A．They are long-lived, high-elevation trees. |
| B．They have a strong resistance to nonnative fungi. |
| C．The government used to care about protecting them. |
| D．They and small insects depend on each other for survival. |
| A．Grizzly bears are no longer threatened. |
| B．The whitebark pines have almost disappeared. |
| C．The population of grizzly bears has increased greatly. |
| D．The government is actually doing nothing to protect bears. |
| A．Better late than never. | B．All roads lead to Rome. |
| C．Never do things by halves. | D．The first step is the hardest. |
| A．Irresponsible. | B．Doubtful. | C．Optimistic. | D．Uncertain. |
7 . More than half the world relies on rice as a main food source. Yet the crop faces an worrying future as global warming increases the Earth’s temperature and adds to more storms, droughts and heat waves, because rice is sensitive (敏感的) to climate extremes and grows in places already experiencing many. Any disturbance to that food source can cause great problems.
The latest report from the Intergovernmental Panel on Climate Change—which brought together 234 scientists to collect recent climate studies—warned that human-caused global warming is happening at an extraordinary pace and is adding to the deadly floods, heat and droughts that we’re already witnessing. And those events result in major risks to farming.
“Higher temperatures lead to increased water loss, resulting in soil drying, increased plant stress and impacts on agriculture, especially in regions where large amounts of rainfall are not expected,” the report states.
If greenhouse gases are not reduced, about a third of global land areas are expected to suffer from at least moderate drought by the end of the century, the report concludes. Some changes like sea-level rise are already locked in.
Rice is especially sensitive to these changes. Rice often grows in ecosystems, such as deltas (三角洲), that have low sea-level and are easy to be influenced by rising seas. Any additional temperature increase could cause sea water into the filed where a healthy crop can develop, scientists say.
A 2018 study in the Archives of Agronomy and Soil Science found that an increase in the frequency and seriousness of hot weather could reduce rice outputs by up to 40% by the end of this century.
“Most of the world’s rice is currently grown in regions where existing temperature is already close to the most suitable range for rice production,” the study states. “Therefore, any further rise in temperature or short period of high temperature during sensitive growth stages will be disastrous.”
1. Why is rice particularly weak to climate change according to the passage?| A．Rice requires large amounts of rainfall. |
| B．Rice is grown in regions with low sea levels. |
| C．Rice is hard to live in places with extreme climate conditions. |
| D．Rice is grown in regions with high levels of greenhouse gases. |
| A．Rising sea levels |
| B．Increased frequency of storms |
| C．Global warming and climate change |
| D．Reduction in greenhouse gas emissions |
| A．Pessimistic | B．Optimistic | C．Uncertain | D．Encouraging |
| A．Rice Output Is Decreasing Heavily. |
| B．Climate Change is Caused by Greenhouse Gas. |
| C．Climate Change Resuits in Low Output of Rice. |
| D．Greenhouse Gas Has Great Effect on Rice Growing. |
8 . Imagine you are on a beautiful tropical beach. The blue water shines in the sun, and the sand is warm under your feet. You notice a small fruit in the sand. It looks like a little green apple. You pick it up and smell it... it smells sweet. But whatever you do. Don’t take a bite!
This is the fruit of the manchineel tree. It is the most poisonous tree in America. You can find it in Florida, as well as in the Caribbean, Mexico, and Central America.
If you were to eat the fruit, it would taste delicious. But then your mouth would start to burn. Your throat would tighten and make it difficult to breathe. You could even die.
The fruit isn’t the only risky part of the manchineel tree. The tree is full of milky white sap. Sap is a liquid that flows through a plant, like blood flows through a person. The manchineel’s sap is hazardous. If it gets on your skin, it will cause painful blisters. So don’t try to cut down these trees, because you could get sap all over you!
And if you try to burn manchineel wood, the smoke will choke and blind you.
Manchineel trees are dangerous, but they’re also an important part of the environments where they grow. Manchineels protect beaches with their strong roots. The roots help stop sand and soil from washing away. This is good for the plants, animals, and people living nearby. There aren’t many manchineel trees left in the world. So even though they’re harmful, people are trying to protect them. Still, if you see one, stay away!
1. What do we know about the manchineel tree?| A．It looks ugly. | B．Its fruit is dangerous. |
| C．Its fruit tastes terrible. | D．It grows in cool places. |
| A．Clear. | B．Smelly. |
| C．Sweet. | D．Unsafe. |
| A．To help people choose fruit. |
| B．To introduce the manchincel tree. |
| C．To improve people’s sense of safety. |
| D．To attract people to tropical beaches. |
1. What is the most important thing when planning a garden?
| A．Growing what one loves. |
| B．Picking the right soil. |
| C．Choosing the location of the garden. |
| A．5. | B．4. | C．3. |
| A．They’re less expensive. |
| B．They grow more easily. |
| C．Their fruits will grow big enough. |
| A．Plant right before the growing season. |
| B．Ask an expert for the right soil. |
| C．Enjoy the process of planting. |
10 . Sunflowers have increasingly become popular on social media. People enjoy the bright yellow flowers and take pictures of themselves in bright fields of sunflowers, which are called “sunflower selfies.”
Actually, it is easy to grow your own sunflowers. Here are some instructions.
Do you want to start growing sunflowers from seeds?
Then, plant each seed into soil apart. Keep the soil wet, but not too wet, until the seeds begin to grow. During the growth process, you should water regularly the plants. When they grow up, it is best to put up some shelves to protect the plants from strong winds.
When seeds will start coming out of the head, it is time for harvest. Cut the flowers off and put them into a bag or container. In this way, the seeds will not fall out. Then remove the seeds by rubbing flowers with your hands or a hard brush over a container.
Finally, you’d better select those full seeds for food.
| A．Equally attractive is the delicious taste. |
| B．Sunflower seeds may be eaten cooked or uncooked. |
| C．You can also tie the plants to something tall for support. |
| D．Some kinds of sunflowers can grow up to three meters tall. |
| E．It is important to loosen the soil before the seeds are planted. |
| F．Put the selected seeds in room-temperature water for 2-8 hours. |
| G．They will develop long roots that work their way deep into the ground. |
