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A new research shows human activity is changing the sound of the Earth's oceans and seas.Scientists say the sound changes of our oceans,seas,and other waterways affect many marine（海洋的）animals—from very small shrimps to huge whales.
Sound travels very far under water,Francis Juanes,an ecologist at the University of Victoria in Canada,told the Associated Press.For fish,he explained,sound is probably a better way to sense their environment than light.Sounds help fish and other marine animals communicate with each other.Sounds also help some ocean animals find food and avoid their hunters.
However,increased noise from humans is making it harder for these animals to hear each other.The noise is coming from shipping traffic,underwater exploration,and other noisy human activities.For many marine animals,their attempts to communicate are being masked（遮蔽）by sounds that humans have produced.Experts explain that masking happens when one or more noises in the water block sound important to a marine animal's living.The overall number of marine animals has gone clown by about half since 1970.Some studies show the stress from human noise might also affect the immune（免疫）system as well as reproductive health or behavior. "Imagine having to raise your kids in a place that's noisy all the time." said Joe Roman,a marine ecologist at the University of Vermont.
When people think of problems facing the ocean,we often think of climate change,plastics and overfishing.But noise pollution is another thing we need pay attention to. "Sound pollution may be easier to deal with than other ocean problems," Scientist Juanes says,"If we make nothing for the ocean,think about how to make it quieter."



Why is sound underwater important for ocean animals？ ______

A. It changes with light.
B. It travels very fast.
C. It helps them judge and contact.
D. It guides fishermen to find where they are.

What does Paragraph 3 mainly tell us？ ______

A. Underwater exploration must be stopped.
B. Kids should experience noise to be healthy.
C. Human noise brings stress to marine animals.
D. Marine animals have got used to sound changes.

What is the author's purpose to write the text？ ______

A. To introduce the benefits of sounds.
B. To show the effects of climate change.
C. To draw attention to sound pollution.
D. To share a method of studying ocean.

What will the author probably tell us in the following paragraph？ ______

A. How to deal with overfishing.
B. What is the main cause of climate change.
C. How to keep the number of marine animals.
D. What should be done to reduce sound pollution.

An advance in electronic publishing could make the book you are reading seem as dated as a silent film.Publishers hope to exploit the growing success of ebooks by releasing versions with added soundtracks and musical accompaniments（伴奏）.
The noises in the first multimedia books include rain hitting a window in one of Conan Doyle's Sherlock Holmes tales.Works by Oscar Wilde and Rudyard Kipling are also available.A Salman Rushdie story with an orchestral score（配乐） will follow this year.In America,works by Shakespeare and Jane Austin have already been released with music and background noise so that,for example,readers can hear tea cups hitting each other in Mr Darcy's garden as they read Pride and Prejudice.
Supporters argue that sound effects are the next logical development for ebooks and will add excitement for younger readers.Critics,however,will argue that the noises will ruin the simple pleasure of enjoying the imagination required to read a book.
Caroline Michel,chief executive of the literary agency PFD，said the new generation of readers was used to multiple sensory input.She said,"Concentration now is such that people have split computer screens where they may be watching television and replying to an email at the same time.If that's what the market wants then we should respond to the market."
Booktrack's sound effects work by figuring out the user's reading speed.Each time you "turn" a page,the software reassesses where you have reached in the text and times the sounds to switch on accordingly.If the soundtrack is not in agreement with the words,a click on any word will re-set it.
Some authors fear a soundtrack could destroy the peace and quiet of libraries and ruin the pleasure of reading.David Nicholls,author of One Day,said,"This sounds like the opposite of reading.I have enough trouble reading an e-book because I'm constantly disturbed by emails and so I've given up on it for the time being."
Stuart MacBride,the crime writer whose novel Shatter the Bones was an e-book bestseller,sells 18% of his books as electronic downloads.He said,"If I'm reading,I will do the noises in my head.I don't need someone to tell me what cutting a tree sounds like.That would upset me."



In whose e-book can we hear the sound of a specific weather condition？ ______

A. Conan Doyle's.
B. Shakespeare's.
C. Salman Rushdie's.
D. Rudyard Kipling's.

What does Caroline Michel think of multimedia books？ ______

A. They go against human nature.
B. They have an unpredictable future.
C. They are in line with market trends.
D. They may inspire readers' imagination.

What's Stuart MacBride's attitude to soundtracks？ ______

A. Indifferent.
B. Disapproving.
C. Appreciative.
D. Disrespectful.

How does the author develop the text？ ______

A. By presenting different opinions.
B. By telling his personal experiences.
C. By giving scientific research results.
D. By comparing various types of ebooks.

Scientists in Michigan have developed a forest fire alarm system.It can not only monitor when a fire begins but also call for help.This battery-free device hangs in a tree and gains all the energy it needs from the natural swinging of branches.Such a sensor（传感器）could watch the woods for a decade without humans' attention.
"For forest fire monitoring,you don't need high amounts of energy," says Cao Changyong,an engineer at Michigan State University,who led the team behind the new device.It recharges itself about every 10 minutes with just enough power to take a measurement.That's plenty of time,Cao says,"to produce enough energy."
There's an obvious need for fast monitoring of faraway forests.Every year,fires burn millions of acres in the United States.Early findings also can save lives.Right now,forest fires are found from satellites or fire towers.Neither,Cao says,is as fast or low-cost as tree-hanging sensors would be.
Cao's group faced some challenges in creating its new sensors.For example,these have to produce enough power to check the forest and send out a signal and that power source has to be used for longer time.To deal with the problems,they decided to change mechanical motion（机械运动）into electricity.The device to do this is known as a TENG short for triboelectric nanogenerator.Scientists have explored TENGS as one way to gain energy from the natural world,including harvesting energy from effects on tabletops,falling rain-even keyboards.The new TENG for forest use produces a current（电流）when a tree branch swings.That current is small,yet enough to power a thermometer（温度计）to monitor the temperature changes signaling fire.
Cao says his team's new model has not yet been tested over long time periods in the real world,but the device is ready.All he needs now is the money to build more of them.



What is special about Cao's sensor？ ______

A. It can save lives.
B. It is shaped like a branch.
C. It is self-powered.
D. It keeps power for about a day.

Which of the following is the benefit of the fire alarm system？ ______

A. Recharging every minute.
B. Monitoring the forest fires.
C. Measuring at a slow speed.
D. Working for a longer time.

What does the underlined word "this" in paragraph 4 refer to？ ______

A. Sending out a signal when a fire breaks out.
B. Producing enough power to check the forest.
C. Turning mechanical energy into electrical power.
D. Monitoring the temperature changes signaling a fire.

What problem is Cao's new model facing for its long-time test？ ______

A. It doesn't work.
B. It is of no use in fact.
C. It needs enough money.
D. It isn't easily performed.

Off the coast of Formentera,an island,lives seagrass that stretches 15 kilometres.The seagrass,covering several hectares,is made up of a single organism.The grasses are also long-lived,for tens or hundreds of thousands of years.Along with two other kinds of coastal ecosystems—mangrove swamps and tidal marshes,seagrass meadows are particularly good at taking carbon dioxide from the air.
This role was highlighted in a report,which was published on March 2nd by UNESCO，on blue carbon—the carbon taken in by Earth's oceanic and coastal ecosystems.In total around 33 billion tons of carbon dioxide,about three-quarters of the world's emissions（排放）in 2019，are locked away in the planet's blue carbon sinks（碳汇）.Research by Carlos Duarte,the report's author and a marine ecologist,has shown that one hectare of seagrass can suck as much carbon dioxide each year as 15 hectares of rainforest.
One reason that blue-carbon ecosystems make such effective sinks is that underwater forests are thicker than the land-based woods.They can also trap floating pieces and organic matter,which settles on the sea floor and can double the amount of carbon stored away.They have another advantage,too.Climate change is leading to more wildfires around the world.As forests burn,their carbon stocks are released back into the atmosphere.Unlike forests on land,blue-carbon ecosystems do not burn.
Blue-carbon ecosystems may not be fired,but they remain affected to other sorts of disasters.In May 2020 hurricane Amphan destroyed 1，200 square kilometres of mangrove forest.A marine（海洋的）heatwave in Australian waters in 2010 and 2011 damaged around one third of the world's largest seagrass meadow in Shark Bay. "Mangrove forests can weaken or control waves and provide natural barriers to storm surges.Protecting and expanding them,then,appears to be a must," said a marine biologist.



What does the second paragraph mainly talk about？ ______

A. The real definition of blue carbon.
B. The special features of the seagrass.
C. The doubt about the blue-carbon ecosystems.
D. The capacity of the blue-carbon ecosystems to store carbon.

Why can the blue-carbon ecosystems make such effective sinks？ ______

A. They aren't influenced by natural disasters.
B. They have great ability to absorb carbon.
C. Their carbon stocks are released back.
D. There are more underwater animals.

What do the marine biologist's words mean？ ______

A. Humans should preserve blue-carbon ecosystems.
B. Mangrove forests can strengthen waves.
C. Mangrove forests are too strong to be broken.
D. Blue-carbon ecosystems can be fired.

What is the best title for the text？ ______

A. Blue-Carbon Ecosystem Are Expanding Much Faster
B. The Grasses Can Store More Carbon Than Your Expectation
C. Mangrove Forests Can Control Waves Efficiently
D. Plants in the Ocean Are Better at Storing Carbon

Water that is on the Earth today is the same water that was here when the Earth began.This is possible because of recycled（可循环的）water,both naturally and as a result of human technology.The Earth naturally reuses its water；however,people use technology to speed up the process through practices like reusing waste water for purposes such as irrigation（灌溉），washing a toilet or filling up a water basin.One of the key advantages of human's recycling water is that it reduces the need for water to be removed from its natural homes such as wetlands.
When you recycle the water that you use in your area,this means that you do not have to take water from other areas.Many areas where pure water is plentiful are places that may suffer when their water is removed.When the water is recycled,it makes it easy for places like the wetlands to keep their water supplies.
Many times,recycling water not only prevents its removal from sensitive environments,but it keeps waste water from going into bodies of water such as oceans or rivers.Reusing waste water prevents it from going directly into the nearest river or ocean where it could spread pollution and do harm to lives in the water.
While waste water can be damaging to rivers and oceans,the Environmental Protection Agency believes that recycled water often contains some nutrients（营养）that are extremely beneficial to irrigating and fertilizing（施肥）fields.Recycled water often contains high levels of nitrogen,which,while being bad for lives in the water,is a required nutrient for plants.
The wetlands provide many benefits to the environment,such as housing wildlife,decreasing floods improving the quality of the water and providing a safe breeding ground for fish populations.Many times,recycled water can be added to the dried wetlands,helping them to once again come to life.



What influence does human's technology have on water recycling？ ______

A. It increases the speed of water recycling.
B. It interrupts the process of water recycling.
C. It makes water recycling more difficult.
D. It lowers the costs of water recycling.

What is the environmental benefit of reusing water？ ______

A. Wetlands grow rapidly.
B. Wetlands are protected.
C. Fertilizer is no longer a must.
D. Water supplies will be various.

Why is recycled water proper for irrigation？ ______

A. It can enrich rivers and oceans.
B. It can be gained easily.
C. It helps kill insects in the fields.
D. It usually contains what plants need.

What is the best title for the text？ ______

A. How can we protect wetlands？
B. What can we do to recycle water？
C. Why is water shortage getting worse？
D. Why is it important to recycle water？

Shakespeare wrote in his great play Hamlet, "Brevity（简洁）is the soul of wit." But it seems that not everyone agrees with this.Microblog has canceled its 140-character limit for posts,meaning users can now write as many words as they like.And now Twitter,a US social media site that's similar to Microblog,also announced that it plans to double its character limit from 140 to 280.
Twitter has its reasons for the changes.It's a pain to have to edit your thoughts to less than 140 characters when you have so much to say.And a big problem for English writers is that it requires more space than character-based languages such as Chinese to express the same thing.According to The Atlantic,while the average English-language tweet is 34 characters,a Japanese one,for example,is only 15.
But still,Twitter users don't seem to be happy with the new move.
Our reading habits have changed over time,and we're used to keeping up to date with what's happening in the world by reading just a couple of lines of text.For this，140 characters are more than enough.
"[Microblogs] are almost always faster and more efficient than television,radio,newspapers,or any other source," wrote Dom Knight,a reporter for The Guardian. "It's like gathering in the town square ...in an instant."
Trying to fit your thoughts into a limited space is also a good way to come up with smart comments,which is why microblogs are often where the best humor is found.
For example,during former US President Donald Trump's election campaign in 2016，a Twitter user wrote："If Trump can seriously win the presidency of this nation,I don't want to see a job description with 'experience required' ever again." And another wrote："England：Nothing can be more embarrassing than Brexit.America：Watch this." These tweets expressed people's upset louder and quicker than any long articles ever could.
So perhaps we should pay attention to Shakespeare's words.After all,he only needed 27 characters to make his famous point.



Why does Twitter plan to change its character limit for each post？ ______

A. Twitter users always have a lot to say.
B. Users are not satisfied with the current character limit.
C. More characters are needed when writing in English than in Chinese.
D. Twitter saw that the benefit after Microblog changed the character limit.

What does "this" refer to in the 4^th paragraph？ ______

A. People want to know what is happening around the world.
B. People prefer to look through short posts rather than read long articles.
C. People are used to reading short posts in order to get the latest news.
D. People's new reading habits make it hard to read long posts.

What is the advantage of Microblog according to Dom Knight？ ______

A. People can get information which they cannot get from traditional media.
B. It can quickly gather various pieces of information for people.
C. It can make people feel as if they are there and experiencing an event themselves.
D. The posts can be easily understood because the characters in each post are limited.

Why does the author write about the two Twitter posts？ ______

A. To show that the US presidential election attracted more attention than Brexit.
B. To explain how British people and Americans show their sense of humor.
C. To prove that Twitter is a platform where you can express your own opinions freely.
D. To offer evidence that limited characters can inspire smart posts.

What is the author's attitude toward the character limit on social media？ ______

A. It should be lifted because it makes it difficult for people to express thoughts.
B. It should be abandoned because it doesn't fit people's current reading habits.
C. It should be kept as Shakespeare argued that using fewer words is better.
D. It is meaningful because short texts fit people's reading habits and help create the best humor.

How often do you exercise？A new study finds that most kids aged 12 to 15 aren't getting enough physical activity.The results are based on about 800 kids.As part of the study,the young teens tracked and reported on their own activity levels,and took physical exams.
The US fitness guidelines recommend an hour or more of physical activity every day.According to the study,only 1 in 4 kids in the US get enough physical activity.
"It's certainly very worrying to see that our kids are engaging in such a limited amount of physical activity each day," said Dr.Stephen Pont.He is an expert on children's health.
Few kids in the survey met the guidelines for physical activity that raises the heart rate and makes them breathe harder.Overall,about 25% said they got an hour of that kind of violent exercise every day.Kids also reported on which activities they did most often outside of the school gym class--basketball for boys and running for girls.
The study found that obese（肥胖的）teens were less active than normal-weight girls and boys.Overweight girls were slightly less active than normal-weight girls,but levels were similar among overweight and normal-weight boys.The study also said that the overall obesity rate for children aged 2 to 19 is 17%，or about 12.5 million kids.
"There's always room for improvement," said health expert Tala Fakhouri,who was the lead author of the study.She also said the results provide useful information to help with fitness campaigns such as Lets Move,which was launched by Michelle Obama in 2010.To inspire kids to eat right and get in shape,Michelle visited schools and held exercise events.She also called on schools to offer regular gym classes.
The study also suggests kids who get physical education at school may get better grades.



What is the result of the new study？ ______

A. It is important to take physical exams.
B. Most US kids don't get enough exercise.
C. Kids should get physical activity every day.
D. 800 kids don't get enough physical activity.

What's the purpose of the campaign Let's Move？ ______

A. To help kids to keep fit.
B. To hold exercise events.
C. To offer regular gym classes.
D. To provide useful information.

According to the study,the children with enough exercise ______

A. do better in their studies
B. try their best to get in shape
C. be more willing to help others
D. be less active than fat children

What does the underlined word "launched" in the sixth paragraph probably mean？ ______

A. visited
B. stopped
C. started
D. improved

Sleep,considered a luxury（奢侈）by many,is essential for a person's wellbeing.Researchers have found that insufficient sleep increases a person's risk of developing severe medical conditions,such as obesity,diabetes（糖尿病），and cardiovascular（心血管的）diseases.Now,a new study by Boston's Massachusetts Institute of Technology（MIT）has found that getting sufficient sleep is also the key to improving academic performance.
Jeffrey Grossman,who led the research was not trying to find the link between sleep and grades when he handed out Fitbits to the 100 students in his introduction to Solid-State Chemistry class.Instead,the professor of Computational Materials Science hoped the popular wrist-worn device which tracks a person's activity 24/7，would show a connection between physical exercise and academic achievement.
However,the study,published in the journal "Science Learning" on October 1，2019，discovered a surprising insight.Then was a straight-line relationship between the average amount of sleep a student got and his/her grade on the 11 quizzes,three midterms,and the final exam administered during the semester.
Even more interesting,it was also not sufficient for students to just head to bed early the night before a test.Instead,it's the sleep you get during the days when learning is happening that matters most.
The time students went to bed each night was similarly important.Those who went to bed in the early hours of the morning performed poorly,even if the total sleep time was the same as a higher-performing student. "When you go to bed matters.Grossman says.If you go to bed after 2，your performance starts to go down even if you get the same seven hours.So,quantity isn't everything."



What is the new finding about sleep？ ______

A. It's essential for a person's health.
B. Sleeping less may cause obesity.
C. Sleeping too much is dangerous.
D. Enough sleep leads to better grades.

What does the underlined word "Fitbits" in paragraph 2 refer to？ ______

A. Wearable devices.
B. Questionnaires.
C. Fitness equipment.
D. Smartphones.

Which of the following best describes the final result the new study？ ______

A. Doubtful.
B. Predictable.
C. Disappointing.
D. Unexpected.

What will benefit students' study according to Grossman？ ______

A. Sleeping for 5 hours each day.
B. Heading to bed at 3 a.m.every day.
C. Getting enough sleep while learning.
D. Going to bed early only before a test.

In 2020，many robots took up jobs,giving both humans and animals a helping hand.
A hospital ward treating COVID-19 patients in Wuhan,China,was run entirely by robots.The robots looked after patients with the lightest symptoms（症状），delivering food for people who work in hospital and keeping the hospital clean.This reduced the risk of doctors and nurses catching the disease.Meanwhile,a robot called Ginger led a dance class for those who were well enough to take part.If a patient fell more seriously ill,they were sent to a human-run part of the hospital for more treatment.
In May,a robot dog enforced（强制实施）social-distancing rules to stop the spread of coronavirus in Singapore.Spot,made by U.S.company Boston Dynamics,served in Singapore's Bishan-Ang Mo Kio Park to check that people kept at least one metre apart from each other.The robotdog was controlled from a distance by a human but may one day be able to work by itself.
In June,a teenager in New Zealand won a national science award for inventing a robot that can take out the bins for elderly and disabled people.Thomas James,who is 17 years old,came up with his great idea after an elderly neighbour was told by a doctor not to take out her wheelie bin（有轮大垃圾桶） in case she fell over.The smart machine took the teenager two years to design and build,using Lego models to test his early ideas.
Over summer,a super-cute SlothBot was tested at the Atlanta Botanical Garden in the U.S.Designed by researchers at the Georgia Institute of Technology,the animal-like robot is powered by sunlight and moves slowly along cables between trees,collecting information about its surroundings.The SlothBot's inventor,Professor Magnus Egerstedt,was inspired after observing sloths（树懒）in Costa Rica.By taking a "creature's-eye view" of life in the trees,researchers hope the robot will help protect endangered forest species in the wild.


What can robots in a hospital ward in Wuhan do？ ______
A. Manage the ward in place of doctors and nurses.
B. Make sure doctors and nurses avoid the disease.
C. Take care of patients with serious symptoms.
D. Offer dance lessons to all patients in the ward.

What does the example of Thomas James tell us？ ______

A. No pains,no gains.
B. Chance favors the prepared mind.
C. Necessity is the mother of invention.
D. Genius is ninety-nine percent perspiration plus one percent inspiration.

For what purpose was SlothBot invented？ ______

A. To remind people to keep a safe social distance.
B. To protect wild forest species that are in danger.
C. To provide service for the elderly and the disabled.
D. To collect information about sloths in Costa Rica.

In which part of a magazine may this text appear？ ______

A. Home news.
B. Entertainment.
C. Animals & Environment.
D. Science&Technology.

Refrigerating meat slows the growth of bacteria,but does not stop it as freezing does.For this reason refrigerated meat is safe to eat for a significantly shorter amount of time than frozen meat.The temperature range from 40°F to 140°F（4.4°C to 60°C）is referred to as the "Danger Zone" by food safety experts.It is in this "zone" that bacteria increase,nearly doubling in a mere 20 minutes.A home refrigerator should be set at 40°F or colder to keep meat safe for the maximum amount of time.It is important to note that/there are two different groups of bacteria that/affect refrigerated meat.The first,pathogenic bacteria（致病细菌），make us sick,while the second,spoilage bacteria（腐坏细菌），make our food go bad and stink up our fridges.By sight,smell and taste,you cannot identify whether a meat is harboring pathogenic bacteria,unlike meat affected by spoilage bacteria.
In a refrigerated state,spoilage bacteria can grow.This is proven by the fact that all food in a refrigerator eventually spoils.Spoiled food won't make you sick - it might taste bad,but unless it has pathogenic bacteria,your digestive system is in the clear.Unrefrigerated meat,if left out on the counter for a few hours,might smell and look fine,but may be full of pathogenic bacteria.During a power-cut,food stored in a refrigerator that rises in temperature to over 40°F for more than two hours should be removed.Also,due to temperature change,don't store meat on the door.It is important to maintain your refrigerator's temperature by keeping the door closed as much as possible.
As always,follow proper cooking instructions when preparing any meat to kill any potentially harmful bacteria.The following is a list of how long certain refrigerated meats will be safe to eat cooked leftovers,four days；raw eggs,three to five weeks；hard boiled eggs,one week；salads,such as egg,macaroni,potato or tuna,three to five days；ham three to seven days；hot dogs,one week if opened,two weeks if unopened；fresh fish/shellfish,one to two days.



What can be inferred from Paragraph 1？ ______

A. Both groups of bacteria can make us sick and nervous.
B. Putting meat in refrigerators can stop the growth of bacteria.
C. it is safer to put meat in refrigerators with a temperature of 10°C.
D. It is easier to know whether meat with spoilage bacteria goes bad.

What effect could you possibly get if you eat spoiled food？ ______

A. You could get food poisoning.
B. You may have a bad taste experience.
C. You may get a digestive system disease.
D. You could get infected by pathogenic bacteria.

What should you do to kill the bacteria when cooking meat？ ______

A. Wash the meat over and over again.
B. Cook the meat according to instructions.
C. Leave the meat on the counter for a while.
D. Put the meat into a refrigerator before cooking.

How long is refrigerated ham safe to eat？ ______

A. Seven to ten days.
B. A week or so.
C. Three to five days.
D. Three to seven days.