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题型:阅读理解-阅读单选 难度:0.65 引用次数:114 题号:16620533

Dandelion (蒲公英) seeds can travel for miles before finally floating down and settling somewhere new. Researchers recently discovered how the plants decide to spread. “We noticed that the dandelion parachute (降落伞) is closed in foggy mornings but then open again when the sun is up during the day,” according to Naomi Nakayama, a researcher of bioengineering. “The dandelion uses a bunch of hairs to improve air drag and aid its flight. Unlike insects or birds, they don’t need any energy input to fly a long distance- even hundreds of kilometers—they simply catch the wind.”

Researchers discovered the parachutes open and close using what they say is like an actuator (触动器), a device that changes energy and signals into movement. But this actuator doesn’t use any energy. The middle of the dandelion’s parachute is able to sense the amount of humidity (湿度) by absorbing water molecules (分子) in the air. Using signals about humidity information, they either open their parachutes and fly off or they close them and stay where they are.

“The center of the parachute changes its shape, moving the hairs altogether in harmony,” Nakayama says. “It’s basically a sponge made of no-longer living plant cells, which are arranged in a tube empty inside. The inner side and the outer side swell with water to different degrees, and that drives the movement.”

Knowing what causes dandelions to spread their seeds could help scientists learn how they deal with climate change. They say understanding the response could help researchers design new soft robots, which are those made from flexible materials that imitate soft bodies. “How plants move their body parts are different from animals and a simple, localized expansion could be enough to move arms,” Nakayama says. “Movement of a few arms has been achieved, but this is the first of many arm actuators. It is simple in design, so there is a lot of space for biomimicry (仿生学)”.

1. What makes the dandelion fly?
A.Energy.B.Wind.C.Fog.D.Parachute.
2. How do the dandelion parachutes decide to work from the second paragraph?
A.By spreading their seeds.B.By changing energy into movement.
C.By feeling humidity information.D.By staying where they are.
3. What can we learn from the last paragraph?
A.Scientists make a robot out of dandelion.B.Plants move just like the animals.
C.Dandelions move with arms.D.Plants can inspire biomimicry.
4. What would be the best title for this passage?
A.Observing DandelionsB.Dandelions and Climate Change
C.Making Soft RobotsD.Dandelions and Biomimicry

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【推荐1】Self-talk helps us all

Talking to yourself may seem a little shameful. If you've ever been overheard criticizing yourself for a foolish mistake or practicing a speech, you'll know the social problems it can cause.     1    

But there's no need for embarrassment. Talking to ourselves, whether out loud or silently in our heads, is valuable. Far from being a sign of insanity, self-talk allows us to plan what we are going to do, manage our activities and control our emotions.

For example, take a trip to any preschool and watch a small girl playing with her toys. Your are very likely to hear her talking to herself: offering herself directions and talking about her problems.     2     We do a lot of it when we are young.

As children, according to the Russian Psychologist LevVygotsky, we use private speech to control our actions in the same way that we use public speech to control the behavior of others. As we grow older, we keep this system inside.

Psychological experiments have shown that this so-called inner speech can improve our performance in tasks like telling what other people are thinking. Our words give us an interesting view of our actions. One recent study suggested that self-talk is most effective when we talk to ourselves in the second person: as "you" rather than "I".

    3     If you want proof, turn on a sports channel. You're sure to see an athlete shouting at himself or herself.

Talking to ourselves seems to be a very good way of solving problems and working through ideas. Hearing different points of view means our thoughts can end up in different places, just like a regular dialogue, and might turn out to be one of the keys to human creativity.

Both kinds of self-talk -- silent and out loud -- seem to bring many different benefits to our thinking.     4    

A.When something comes from within you, you always try your best to analyze it in a scientific way.
B.Psychologists call this private speech -- language that is spoken out loud but directed at yourself.
C.So words to the self, spoken silently or aloud, are so much more than just chatter.
D.We keep the private speech we use as children inside -- but we never truly put away the out-loud version.
E.According to the well-known saying, talking to yourself is the first sign of madness.
F.Self-talk is efficient because when we are vocal about our thoughts, it makes a larger impact on our brain.
2021-03-31更新 | 80次组卷
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【推荐2】Outdoor lighting in general poses a deadly threat to insects. That’s according to a study published online in November 2019 in the journal Biological Conservation, entitled “Light Pollution Is a Driver of Insect Declines”.

The article notes that sudden drops in insect numbers around the world have happened over the past couple of decades in what amounts to an insect destruction. The blame is usually assigned to “habitat loss, chemical pollution, invasive species, and climate change”. But the authors argue that the forces of lightness have not gotten their due.

A longtime preference among ecologists for studying daytime phenomena, and a preference for sleeping at night has led insect conservationists to overlook another widespread habitat disturbance, pollutant, and method of insect control: artificial light at night(ALAN).

ALAN’s influence occurs through its interference with the development, movement, foraging, and reproductive success of diverse insect species. Another factor is light’s positive effect on insectivore predation. That is, birds, bats, amphibians and arachnids aren’t stupid-if a lot of insects start swirling around lights in the night, predators will also show up.

Sadly, ALAN increases sharply after Thanksgiving, as many people add festive illumination(照明) to the exterior of their houses to celebrate the approach of Christmas. Many neighborhoods have a particular house that embraces the spirit of the season in such an outsized way as to produce a radiant haze perhaps visible to hunters in other star systems.

The task then must be to lessen the ecological consequences of ALAN on insects while still maintaining sufficient levels of nighttime illumination for human safety and enjoyment.

“Monochromatic LEDs can be engineered to produce light of any desired spectral composition,” the investigators write. “Therefore, once we know the specific wavelength affinities of insects, we can in theory design lights with minimal output in the wavelengths that most affect insect fitness.”

Turning some of the lights off might also help. In many cases, it is far easier, quicker, and cheaper to block, dim, or turn off a light source than it is to find the particular bulb type or narrow bandpass filter(滤波器) that makes its emissions visible to humans alone. Help end the war on insects. It is better to blow out one candle than to curse the planet.

1. We can know from Paragraph 2 that ________.
A.lights are to blame for insect decrease
B.lightness hasn’t got the attention it deserves
C.lightness hasn’t caused environmental problems
D.the dying out of insects is too slow to be noticed
2. What can we learn from the passage?
A.Most insects enjoy the lights at night.
B.Birds and bats cannot hunt without light.
C.Lights in the night make insects easily caught.
D.Lights in the night has positive effect on insects.
3. What solution is proposed in the passage?
A.To make lights only visible to human.
B.To use candles instead of light bulbs at night.
C.To reduce light resource by turning off some lights.
D.To change the light bulbs into ones with special light.
4. What might be the best title for the passage?
A.The importance of light to insects
B.The main causes of insects’ decrease
C.To light, or to candle, that is the question
D.Too much illumination is killing vital insects
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【推荐3】Greenhouse gas emissions would rise if all farms in England and Wales went organic. Though the emissions of each farm would go down, much more food would have to be imported, as the amount they would produce would decrease greatly.

“The key message from my perspective is that you can't really have your cake and eat it,” says Laurence Smith, now at the Royal Agricultural University in the UK, who was part of the team that ran the numbers. Smith is a supporter of organic farming and says “there are a lot of advantages of the organic approach”, but his analysis shows that organic farming has downsides too.

Farming and changes in land use, such as cutting down forests, are responsible for a third of all greenhouse gas emissions. That means reducing farming emissions and the land needed for farming is required to limit further global warming.

Smith and his colleagues found that emissions per unit of food are, on average, 20 per cent lower for organic crops and 4 per cent lower for organic animal products. However, organic harvests per hectare (公顷) are also lower on average. For wheat and barley, for instance, harvests are just half of those of traditional farms. This means 1.5 times as much land would be needed to grow the same amount of these foods.

The estimated increase in emissions varies greatly, depending on where the extra farmland comes from. If only half comes from turning grassland into farms, the increase could be as low as 20 per cent. If grassland that would otherwise have been reforested is turned into farmland, emissions could nearly double.

This doesn't necessarily mean people should stop eating organic produce, says Smith. People might choose organic food for other reasons, such as to reduce their pesticide exposure (though contrary to popular belief, organic farmers do use pesticides) or for the sake of wildlife.

Smith says the best choice may be to use some organic and traditional farming methods at the same time.

1. Why may greenhouse gas emissions increase if a country goes organic?
A.Organic farms take longer to build.
B.The agricultural output will increase greatly.
C.The emissions of each farm unit will increase.
D.Greater demand for imported food will be created.
2. What does the underlined word “downsides” in Paragraph 2 probably mean?
A.Changes.B.Challenges.C.Disadvantages.D.Differences.
3. What did Smith and his colleagues find?
A.Organic harvests per unit are greater than traditional harvests.
B.Organic farming needs more farmland to feed a country.
C.Global warming could be brought under control.
D.Land was not used in a responsible way.
4. What is Smith's suggestion?
A.Stopping using pesticides.
B.Eating less organic produce.
C.Going back to traditional farming.
D.Adopting mixed farming methods.
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