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One of the greatest mysteries in science is just how Earth went from a planet with minimal oxygen to the breathable air we have now. Scientists long figured that cyanobacteria (蓝细菌) were involved, but couldn’t tell what started the great oxygen-producing cycle.

A new study published in Monday’s Nature Geoscience may provide the key. It theorizes that Earth’s gradually lengthened day from six hours to the current 24 hours kick-starts cyanobacteria into producing lots of oxygen, making most of life as we know it possible. Here are the takeaways of the study.

About 2. 4 billion years ago, there was so little oxygen in Earth’s atmosphere that it could barely be measured, so no animal or plant could live. Instead, lots of bacteria breathed in CO2, and in the case of cyanobacteria, produced oxygen in the earliest form of photosynthesis (光合作用).

At first it wasn’t much. But in about 400 million years, as Earth’s rotation (旋转) gradually slowed down and the day was lengthened from six hours to the present 24 hours, the cyanobacteria breathed more and more oxygen into Earth’s atmosphere until it reached one-tenth the amount of oxygen we have now. The increased oxygen allowed plants to join in the oxygen-making party.

The authors of the study put their theory to test with the bacteria found on a 24-meter-deep seabed in Lake Huron. They exposed the smelly bacteria, which are very similar to the cyanobacteria living around 2. 4 billion years ago, to varying amounts of light, and found that the more continuous light the bacteria got, the more oxygen they produced.

“What makes the idea so convincing is that it doesn’t require any big biological changes in bacteria or the world’s oceans,” said Tim Lyons, a professor at the University of California, Riverside, who wasn’t part of the research team. “This may be a simple but plausible explanation for Earth’s oxygen increase.”

【小题1】What started the oxygen-producing cycle according to the new study?
A.Earth’s faster rotation.B.The lengthened daytime.
C.The bacteria in Lake Huron.D.The appearance of plants on Earth.
【小题2】What is the main purpose of the experiment?
A.To protect the cyanobacteria.B.To study the similarities of the bacteria.
C.To provide evidence for the theory.D.To improve the oxygen level on seabed.
【小题3】What does the underlined word “plausible” in the last paragraph mean?
A.Reasonable.B.Sincere.C.Complex.D.Unacceptable.
【小题4】Which of the following is a suitable title for the text?
A.The Rotation of Earth Is Slowing Down
B.Cyanobacteria’s Role Has to Be Re-examined
C.A Breakthrough Is Achieved in Ocean Protection
D.Earth’s Slowing Rotation Increased Oxygen Production
2022·河北·模拟预测
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A phrase “less screen time and more green time” is popular now. A study from the University of Adelaide found that more time outside and less time spent watching TV is connected with better psychological (心理的) results and school achievements among teenagers. Gardening is a great way to do so.

Jim Carter, a psychologist of America, is asking for teenagers’ return to traditional values of gardening, and thinks that they need to turn off the TV and go outside to do something healthier instead. Carter even considers it important to put gardening as a usual course because it is proven to be good for mental health.

“It’s physical exercise, and it teaches patience,” Carter explains. “The wait for a small sunflower seed (葵花籽) to become a six-foot plant is long.”

“I’m hearing that teenagers are struggling to deal with stress, and every time they open Gardeners’ World, they talk about how gardening helps them deal with stress. They learn so much about life, and so much about themselves through gardening,” said Lee Connelly, a teacher who is carrying out his own green school programme—Gardeners’ World. “The join of gardening into the class course for schools presents a remarkable chance to change education and the benefits are far beyond the classroom, influencing mental health, behavior and developing a lifelong love for horticulture (园艺).”

【小题1】What does Carter suggest teenagers do?
A.Go back to gardening.B.Do exercise at home.
C.Turn on the TV at night.D.Pay attention to psychological courses.
【小题2】Why does Carter mention the sunflower seed?
A.To prove gardening is easy.B.To explain gardening develops patience.
C.To show green time is hard to find.D.To say dealing with stress is difficult.
【小题3】What can we say about Lee Connelly’s green school programme?
A.It is useless.B.It is meaningful.C.It is costly.D.It is challenging.
【小题4】What is the most suitable title for the text?
A.Gardening: A Good Green Moment for TeenagersB.Time to Get Close to TV
C.Less Screen Time, Better School AchievementsD.Being Sporty, Being Healthy

You’ve probably heard this before. In a society that praises productivity and business, it seems funny to talk about being bored as a good thing. We like being productive, but moments of boredom are actually good for our lives. Here are the reasons:

Boredom is necessary for creativity.

Often new ideas come to you when you let go of doing or thinking too much. It feels like they come out of nowhere, but they are actually born when you’ re bored or when you’re looking for something fresh. 【小题1】 It’s because they get bored so easily and, want to try something else.

Boredom can help you with your productivity.

The two aren’t exclusive, but they complement(补充)each other. They’re often like yin and yang if you will.【小题2】   Having one without the other could have a harmful influence on us.

Being bored encourages reflection.

【小题3】 It can also encourage you to think a lot about yourself, which will help you see where you’ re headed. It’s like taking a break from your actions and seeing them like an outsider.

【小题4】

Our brains need to cool down and take a break from everything. And what better way to do this is there than taking a break or going to sleep? Feeling bored can give you a better chance of getting a good night’s sleep. Waking up rested the next day will only increase your productivity. 【小题5】.

A.No wonder kids can be so creative.
B.Boredom can help you get some rest.
C.Boredom teaches you about time management.
D.You will feel like giving your boredom a big thanks.
E.People usually can’t sleep because their minds are too active.
F.Boredom can help you look within more and examine what’s in there.
G.Moments of activities require moments of slowing down and doing nothing.

Handwritten notes in class might seem outdated as digital technology involves nearly every aspect of learning. But a steady stream of research suggests that compared with typing, taking notes with pen and paper is still a better way to learn. And scientists are zeroing in on why.

In a recently published study, scientists found that those writing by hand had higher levels of electrical activity across many interconnected brain regions. They added 256 sensors into a hairnet, which helped monitor 36 students’ brains as they wrote or typed words displayed on a screen. When students wrote by hand, the sensors picked up widespread brain connectivity including visual regions, regions that receive and process sensory information, and the motor cortex (运动皮层) . Typing, however, resulted in minimal activity in these brain regions.

Across many contexts, studies have shown that students appear to learn better when they’re asked to produce letters or other visual items using their fingers and hands. The educational neuroscientist Sophia Vinci-Booher says the recent study highlights the clear tie between motor action and conceptual recognition: “As you’re drawing a letter or writing a word, you’re taking this perceptual (感知的) understanding of something and using your motor system to create it. That creation is then fed back into the visual system, where it’s processed again — strengthening the connection between an action and the images or words associated with it.”

The new findings don’t mean technology is always a disadvantage in the classroom. Laptops, smartphones, and other such devices can be more efficient for writing essays and can offer fairer access to educational resources. But people now increasingly tend to “offload” mental tasks to digital devices, such as by taking a photograph instead of committing information to memory, says Yadurshana Sivashankar at the University of Waterloo in Ontario. “If we’re not actively using these areas, then they are going to worsen over time, whether it’s memory or motor skills.”

【小题1】What is the function of the sensors in the recent study according to Paragraph 2?
A.To record brain activity.B.To activate brain waves.
C.To connect visual regions.D.To process sensory information.
【小题2】What is the finding of the recent study according to Sophia Vinci-Booher?
A.One’s motor system boosts his creativity.B.One’s writing action enhances his perception.
C.Learning performance relies on visual memory.D.Concrete images contributes to comprehension.
【小题3】What does the underlined word “offload” in Paragraph 4 mean?
A.Owe.B.Link.C.Shift.D.Bring.
【小题4】Which of the following can be the best title for the text?
A.Note-taking: the key to a good gradeB.Digital learning: beneficial or harmful
C.Typing vs handwriting: efficiency countsD.Handwritten notes: conventional but effective

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