1. How many people died in a landslide in 2003?
A.About two hundred. | B.Over one thousand. | C.About two thousand. |
A.Growing grass. | B.Cutting down trees. | C.Growing population. |
A.Growing more forests. |
B.Chopping down the old forests. |
C.Getting busy in protecting our country. |
2 . Between 20 and 40 per cent of planet Earth is covered in grasslands, across every continent except for Antarctica. Grass is a low-growing, flowering plant with groups of narrow leaves growing from its base. Strong roots typically hold this plant’s leaves firmly to the ground.
One of the most common sights along stretches of grass is grass-eating animals. This is because many large animals rely on extensive grasslands to survive, and grass grows well with this regular trimming (修剪). The plants gain their energy from sunlight and require healthy cells to do so. If the leaves aren’t cut, the tips die and start to rot. When they are damaged with a clean cut, however, the cells are caused to grow quicker and produce new, healthy tissue. This is also why cutting your garden’s grassland regularly can make your grass look thicker and healthier.
Humans rely on grass for food, too. Many grasses, such as w heat or corn, are harvested as a main part of some diets. Meanwhile, grass is used indirectly to produce food in the form of livestock (牲畜). Cattle farmers require grass in their fields to feed cows and sheep before they are turned into meat for human consumption.
One of the most debated questions is how long ago grass evolved. Because grass doesn’t preserve well as a fossil, a definitive answer is hard to come by. Until recently, many scientists estimated that grass began to grow on Earth between 50 and 65 million years ago.
However, within the last decade, a piece of 100-million-year-old amber (琥珀) was found that appeared to contain the oldest grass fossil to date. Studies of fossilized dinosaur faces (粪便) also suggest that some dinosaurs lived at the same time that grass grew on the planet, incorporating it into their diets.
1. What is the function of the roots mentioned in Paragraph 1?A.To fix the leaves to the soil. | B.To store water and nutrients. |
C.To support the growth of the plant. | D.To protect the plant from animals. |
A.By improving soil quality. | B.By encouraging cell growth. |
C.By preventing the tips from dying. | D.By attracting more animals to eat them. |
A.Grass doesn’t preserve well as a fossil. | B.There are no fossils of grass available. |
C.There is no solid evidence of its evolution. | D.Scientists can’t agree on its origin. |
A.The Variety of Grass | B.The Development of Grass |
C.How Grass Change Life | D.How to Make Grass Grow Well |
1. How does the woman feel at first?
A.Curious. | B.Surprised. | C.Excited. |
A.Flowers. | B.Mushrooms. | C.Trees. |
A.Two. | B.Three. | C.Four. |
A.On Thursday. | B.On Friday. | C.On Saturday. |
4 . 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. |
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. |
A.They can recongnize harmful vibrations. | B.They look like laboratory mice. |
C.They can threaten the caterpillars. | D.They can release poisonous chemicals. |
A.Disadvantages of chemical pesticides. | B.Application of the experimental results. |
C.Interaction between plants and insects. | D.Warning system of widespread insects. |
5 . Some of the oldest living things on our remarkable planet are trees. The record holders are bristlecone pines (狐尾松) of the western United States, quite a few of which are known to be more than 3,000 years old. One individual, discovered in 2012, is estimated to be more than 5,060 years old, making it the oldest known non-clonal tree in the world!
So, how do trees survive for thousands of years?
The other part of the answer has to do with how trees age. In fact, there is quite a debate about whether ancient trees can be considered “immortal (永生的)”. That is, will such trees ever die if they are not killed by an outside force? We may never know the answer to that, but, at the very least,
Older trees benefit greatly from having bodies made mostly of dead woody tissue. In fact, an old tree might be as much as 95 percent dead tissue! Given that it isn’t alive, wood does not require metabolic (新陈代谢的) activity to maintain it,
A.so an old tree doesn’t really need to do much to keep living |
B.This is a question that has something to do with the good luck of trees |
C.However, bristlecones are certainly not alone in terms of the oldest creatures |
D.This is a fascinating question for biologists that does not yet have a settled answer |
E.What’s more, some ancient trees have superior chemical defenses against pests and diseases |
F.which means that trees can survive everywhere without being limited by external and internal conditions |
G.we know that ancient trees age in ways that are dramatically different from the ways that most animals and even other plants age |
6 . Scientists have shown how plants can protect themselves against genetic (基因的) damage caused by environmental stresses. The growing tips of plant roots and shoots have an in-built mechanism (机制) that spells cell death if DNA damage is detected, avoiding passing on faulty DNA.
Plants have small populations of stem cells (干细胞) at the tips of their roots and shoots, which enable them to continuously grow and produce new tissues throughout their lifetime. These stem cells serve as ancestors for plant tissues and organs. However, any genetic faults present in the stem cells will continue to exist and be passed on permanently throughout the plant’s life, which could last thousands of years.
Given the critical role of stem cells and their exposure to potentially dangerous environments at the growing tips of roots and shoots, safeguards are necessary to prevent stem cell faults from becoming fixed. Researchers Nick Fulcher and Robert Sablowski, funded by the Biotechnology and Biological Sciences Research Council, aimed to uncover these protective mechanisms. Through experiments involving X-rays and chemicals, they discovered that stem cells were more sensitive to DNA damage compared to other cells.
When DNA damage occurs, the cells have the capacity to detect it and cause programmed cells to die, preventing the propagation of the damaged genetic code to the rest of the plant tissues. This process has similarities to the safeguard mechanism found in animal cells, which has been broadly studied due to its relevance in preventing cancer.
The identification of a similar protective system in plants is of great interest in the field of plant development. It also helps scientists develop plants that can better handle environmental stress. So knowledge of how plants deal with these stresses is of fundamental significance to agricultural science’s response to climate change.
1. What is the function of the in-built mechanism in plants?A.To produce more roots and shoots. | B.To increase the overall lifetime of the plant. |
C.To enhance plant growth and nutrient intake. | D.To stop genetic faults in stem cells passing on. |
A.They are relatively abundant in quantity. | B.They are resistant to environmental stresses. |
C.They make quick response to DNA damage. | D.They have the ability to repair damaged DNA. |
A.Spread. | B.Change. | C.Existence. | D.Self-repair. |
A.The way of dealing with climate change on the earth. |
B.The significance of identifying the protective system in plants. |
C.The method of ensuring plant survival under environmental stress. |
D.The urgency of developing plants that can handle environmental stress. |
7 . Imagine if your houseplant was thirsty and it could tell you so. Chances are, it can—you just can’t hear it. According to the findings from researchers in Israel, tomato and tobacco plants stressed from lack of water or having their stems (茎) cut make sounds comparable in volume to normal human conversation.
The sound is kind of a snap (咔嚓声) and pop. While the frequency of the plant outcry is too high for our ears, they can likely be heard by insects, other animals and other plants.
The team started with healthy and stressed tomato and tobacco plants—the stressed ones were either unwatered for several days or had their stems cut. They recorded the group in an acoustic chamber (隔音箱) and then in a noisier greenhouse. They also used a machine-learning algorithm (算法) to distinguish between happy plants, thirsty plants, and cut plants.
The team found that stressed plants make more sounds than unstressed plants, with a stressed plant making 30 to 50 clicks per hour at seemingly random intervals. Unstressed plants were much less active.
“Water-stressed plants began making noises, and the frequency of sounds peaked after five days with no water before decreasing again as the plants dried up completely. The types of sound differed with the cause of stress,” according to a press release for the research. “The machine-learning algorithm could accurately distinguish between lack of water and stress from cutting and could also tell whether the sounds came from tomato or tobacco plants.”
The researchers explain that it’s unclear whether the sounds result from an effort to communicate—yet they note that the sounds have ecological and evolutionary meaning. “It’s possible that other organisms could have evolved to hear and respond to these sounds,” says Hadany. “For example, an insect that intends to lay eggs on a plant or an animal that intends to eat a plant could use the sounds to help guide their decision.”
1. What did the Israel researchers find?A.Plants cry loudly when they are cut | B.Certain plants like to help each other. |
C.Plants communicate as humans do. | D.Certain stressed plants make sounds. |
A.Why a noisier greenhouse was used. | B.How the researchers did the research. |
C.The importance of recording the plants. | D.The varieties of plants for the study. |
A.The moment they were lack of water. | B.When the experiment began. |
C.After five days of water shortage. | D.After drying up completely. |
A.They are of much significance, | B.They help animals escape danger. |
C.They affect the ecological balance. | D.They are mainly for communication. |
1.古树保护的意义;2.古树保护面临的问题;3.你的建议。
注意:1.词数100左右;2.可以适当增加细节,以使行文连贯。
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9 . A new kind of hybrid wheat now available to American farmers may help reduce fears over genetically engineered crops. The new hybrid wheat is being introduced as seed companies worldwide seek to increase production because of reducing grain supplies. The hybrid wheat was developed by a Chinese-owned agriculture company. The product was created without genetic engineering. The first seeds to grow the wheat will be released on 2, 000 to 2, 800 hectares of American farmland next year, according to Reuters reports.
Developers or breeders create hybrid wheat by taking away the natural ability of plants to pollinate (授粉) themselves. Instead, female wheat plants in a field are pollinated by male plants of a different line. The goal of the process is to create seeds that can produce bigger crops and better resist harmful environments. The fertilized female plants produce a new kind of hybrid. Using this hybrid technology permits breeders to choose the best elements from two parent seeds to produce new seeds containing the best characteristics of both.
Producers say when seed companies produce hybrid wheat seeds, some female plants often fail to become fertilized because they depend on unpredictable winds to carry pollen (花粉). Pollen is a substance produced by plants when they reproduce. During some seasons, pollen is released into the air and carried to other plants to be fertilized. Producers say the fertilization of each plant is more certain during wheat’s natural process of self-pollination.
Researchers say the new hybrid wheat has to take long to come to market because the development process is more costly and complex. It could be important in increasing wheat yields and avoiding being linked to GMO development. GMO stands for genetically modified (改进的) organism. Genetically modified wheat has never been grown for industry purposes because of fears that allergens or poisons might be created. Wheat is used to make numerous major foods worldwide.
Dave Hankey owns a seed company in Park River, North Dakota. He told Reuters, “Because of the resistance to genetically modified stuff, the hybrid wheat would be considered better and safer.” He added it would certainly be the public view.
1. Which of the following leads the new hybrid wheat to be developed?A.The existing unsafe grain. |
B.The decreasing output of food. |
C.The application from American farmers. |
D.The Chinese agriculture company’s proposal. |
A.Requiring less fertilizer. |
B.Producing more but smaller crops. |
C.Improving their natural ability of self-pollination. |
D.Having better adaptability to the environment. |
A.It is simple and fruitful. | B.It is complex but low-cost. |
C.It is challenging but worthwhile. | D.It is temporary and limited. |
A.Critical. | B.Tolerant. |
C.Supportive. | D.Cautious. |
10 . Warmer oceans can cause coral (珊瑚) bleaching. Bleaching happens when the coral, colonies of tiny animals called polyps, lose colored algae (藻类) living in their bodies and turn completely white. Without the algae, the coral loses its main food source and can die.
In 2021, the United Nations reported a 14 percent loss of corals across the world largely from rising sea temperatures in the previous 13 years. Australia declared mass bleaching events in 2022 across large parts of the Great Barrier Reef, the fourth since 2016.
Reefs in Hawaii, Florida, and the Caribbean were all severely affected, but thankfully some coral areas were not. Scientists looked into the characteristics of these corals and their ecosystems to see how others could be protected. Warm water reefs in the tropics are the worst affected by bleaching, but they also contain corals with better heat resistance.
Research is focused on finding genes for heat tolerance so that they can be passed on to future generations. Biologists mix corals that are more resilient to higher temperatures with those that are not and the resulting hybrid generation has a better chance of survival.
Researchers in Florida’s reefs have been using ocean nurseries to replant coral with batches that contain genes resistant to heat, acidification, and disease. Those areas have recovered within a year.
Other projects like Revive and Restore are using methods like preserving older coral populations’ sperm and eggs (biobanking) and using corals with better adaptability characteristics in breeding. The project also believes that boosting biodiversity by restoring (恢复) seabirds to islands, and ridding them of invasive species like rats, helps coral reefs thrive.
Ultimately, scientists say that without a serious reduction in greenhouse gas emissions, 99 percent of the world’s coral reefs will be gone by the end of the century. There is a limit to how quickly coral can adapt, especially given the rate of climate change. Computer simulations have shown that mild or moderate warming allows coral to adapt, but if temperatures rise rapidly then extinction is certain.
1. What mainly causes coral bleaching?A.Loss of algae. | B.Lack of food. |
C.Warm oceans. | D.Ocean pollution. |
A.Coral reefs in tropics are easier to bleach. |
B.Some corals are found better to resist heat. |
C.Coral reefs in some areas are badly affected. |
D.Ecosystems in some coral areas are destroyed. |
A.Breeding hybrid generation with heat resistance. |
B.Replanting batches of corals containing diseases. |
C.Restoring seabirds of islands and invasive animals. |
D.Setting no limitation of greenhouse gas emissions. |
A.Botany. | B.Culture. | C.Nature. | D.Education. |