【推荐2】When Omar Yaghi was growing up in Jordan, his neighborhood received water for only about 5 hours once every 2 weeks. If Yaghi wasn’t up at dawn to turn on the taps to store water, his family, their cow, and their garden had to go without. At a meeting last week, Yaghi, now a chemist at the University of California, reported that he and his colleagues have created a solar-powered device that could provide water for millions in water-stressed regions. At its heart is a porous crystalline   (多孔晶体) material, known as a metal-organic framework (MOF), which acts like a sponge: It sucks water vapor out of air, and then releases it as liquid water.

Yaghi and his colleagues first developed a zirconium( 锆 )-based MOF in 2014 that could harvest and release water. But at $160 per kilogram, zirconium is too expensive for massive use. So, last year, his team came up with an alternative called MOF-303, based on aluminum, which costs just $3 per kilogram, but the harvest was only about 0.2 liters per kilogram of MOF per day.

In July 2019, Yaghi reported that his team has designed a new and far more productive water harvester. Supported by a solar panel to power a fan and heater, which speed the cycles, the new device produces up to 1.3 liters of water per kilogram of MOF per day from desert air. Yaghi expects further improvements to increase that number to 8 to 10 liters per day. And his company plans to release a microwave-size device able to provide up to 8 liters per day this fall. The company promises an enlarged version next year that will produce 22,500 liters per day, enough to supply a small village.

However, it needs to be shown that Yaghi’s MOFs can be produced cheaply on a large scale. Each potential commercial MOF needs to prove itself in stability, efficiency, and life span. But if MOFs can pass those tests, they could offer a solution to some of the world’s most pressing problems.

1. Why is Omar Yaghi’s childhood mentioned at the beginning?

A．To show how serious water problem is.	B．To lead in the topic.
C．To introduce the chemist.	D．To arouse reader’s interest.

2. What is the problem of MOF-303?

A．It costs too much.	B．It can’t last long.
C．It is hard to operate.	D．It is low in efficiency.

3. According to Yaghi, how much water will a large water harvester produce per day?

A．1.3 liters.	B．10 liters.
C．22,500 liters.	D．8 liters.

4. What can be concluded from the last paragraph?

A．Yaghi’s MOFs are in great demand now.

B．Yaghi’s MOFs may help solve water shortage.

C．Yaghi’s MOFs have already entered the market.

D．Mass production of Yaghi’s MOFs is impossible.

【推荐3】A new color changing ink could aid in health and environment monitoring for example. allowing clothing to switch colors when exposed to sweat or a woolen blanket to shift colors if a dangerous gas enters the room. The ink could be printed on anything from a T-shirt to a tent.

Wearable sensing devices like smart watches use electronics just to monitor heart rate, blood sugar. and more. Now researchers at Tufts University's Silklab say the new silk-based ink can respond to. and quantify the presence of chemicals on or around the body. “Silk has the ability to add necessary sensing and color changing chemical substances to the ink without losing their functions. " says Fiorenzo Omenetto. a biomedical engineer at Silklab.

The researchers improved on an earlier repetition that worked with inkjet printers, thickening the ink with a chemical to make it capable for screen printing. and then added various reactive substances. With the new ink, they can now easily print a large number of reactive elements onto large surfaces.

The team made the ink by breaking down raw silk fibers into proteins, which the researchers suspended in water. Next they mixed in various reactive molecules (分子) and analyzed how the resulting products changed hues when exposed to changes in their environment. When printed on fabric. pH indicators, for example. could convey information about skin health and a wearer s tiredness levels. The changes are visible to eyes. but the researchers also used a camera- imaging analysis to continuously monitor the color variations and create a database of values.

Omenetto says that the ink could be adapted to track environmental changes in a room, or to respond to bacteria and follow disease progression.

Mechanical engineer Tyler Ray of Hawaii University notes that most of today's wearable monitors are rigid, fairly large and heavy. "The new ink technology has the potential to transform consumer wearable monitors from entertainment devices into body worn, clinical grade physiological measurement tools providing useful information and making it easier for physicians to operate. " he says.

1. What can the new ink be used for?

A．Making pictures,	B．Printing documents.
C．Breaking down fibers and proteins.	D．Detecting health and environment changes.

2. What does Fiorenzo Omenetto mention in paragraph 2?

A．The chemical substances in silk.

B．The practical functions of smart watches.

C．The role of silk in the new ink technology.

D．The influence of the new ink on the human body.

3. What does the underlined word “hues" in paragraph 4 probably mean?

A．Levels.

B．Colors.

C．Wearers.

D．Analysis.

4. How does Tyler Ray expect of the wearable monitors using the new ink?

A．Practical.

B．Soft.

C．Large and heavy.

D．Small but inconvenient.

【推荐2】Eastern barred bandicoots (袋狸) once were a common sight in the plains of western Victoria and into South Australia. But by the 1980s, just one population of between 150 and 200 bandicoots survived.

In 1988, the Victoria state government formed a recovery team that brought together government agencies, Zoos Victoria, volunteer groups and other people. That year, scientists removed 40 bandicoots from this population to form a captive breeding (圈养繁殖) program. Soon after, eastern barred bandicoots disappeared from the wild in Victoria. The only remaining breeding population existed in small pens at Woodlands Historic Park. “Without the captive program, the species would be extinct.” Scientists say.

Breeding was one thing. Re-establishing wild populations was altogether more difficult. Six times captive-born bandicoots were set free into the wild. All six reintroductions failed when foxes killed the bandicoots.

What changed everything was the reintroduction of bandicoots to Phillip Island in 2017 and French Island in 2019. Fox-free French and Phillip islands offered just over 70 square miles of bandicoot habitat, and the bandicoots have already begun breeding and expanding (扩大) their range across these islands.

After scientists had established populations on islands, researchers looked to expand their efforts to open grasslands. In 2015, David Williams began training his Maremma dogs. The idea worked this way: Because bandicoots live alone, the Maremmas would look after sheep in large open grasslands where bandicoots lived. As long as there were sheep in the bandicoots’ territory (领地), the Maremmas remained, and as long as the dogs were around, the foxes were far less likely to remain.

Over the past two years, the recovery team has reintroduced 40 bandicoots into two places in western Victoria, with two to three Maremmas and hundreds of sheep at each site to keep them company. Scientists can’t yet say whether the experiment is working. But some of the bandicoots have bred, and initial camera-trap evidence suggests that foxes, if they pass through the area at all, rarely stay for long.

1. What is the main idea of Paragraph 2?

A．Eastern barred bandicoots became extinct in the wild.

B．The 1988 captive breeding program saved the species.

C．The government played a role in protecting the species.

D．Combined efforts made no difference to the environment.

2. What led to the failure of all 6 bandicoot reintroductions?

A．Food shortage.

B．Lack of habitats.

C．Threats of natural enemies.

D．Insufficient captive-born bandicoots.

3. Why did William train Maremma dogs?

A．To take good care of his sheep.

B．To keep bandicoot out of fox territory.

C．To help dogs and bandicoots live in harmony.

D．To reintroduce bandicoots to the open grasslands.

4. What can be inferred about the program in western Victoria?

A．It has completely failed.

B．Its result remains to be seen.

C．It turns out an instant success.

D．Its process needs closely monitoring.

【推荐3】The Intergovernmental Panel on Climate Change released a report stating that the world is quickly running out of time to keep global warming below 1.5 degrees Celsius. To get there, the world would have to cut current emissions by 45 percent by 2030. That sounds absurdly unlikely.

But before we give in to despair, we should remember that the technology to address climate change is going along at a high speed. The largest source of U. S. carbon emissions is transportation, and a Green New Deal for motor vehicles would be quite straightforward.

The reason is simple: with some subsidies(补贴), electric cars and buses are now cost-competitive with fossil-fuel vehicles. Electric buses have made the greatest speed into the market, because they are a logical choice for electrification. By the end of 2018, electric vehicles were displacing about 280.000 barrels of oil demand per day——about 84 percent of which was due to buses.

But the electric car market is also reaching maturity(成熟), with appealing designs, longer range, and a quickly-expanding rapid charging network in many countries. It’s worth emphasizing that most of the infrastructure(基础设施) necessary to recharge electric vehicles already exists. People often tend to assume that we would need to replace every gas station, but virtually all homes and businesses already have an electrical connection which can be easily improved for fast charging. All that is needed to go fully electric is enough battery capacity and fast charging stations to deal with long trips.

Now America would have to repair its electricity production, freight rail, shipping, and so on to fully decarbonizes(脱碳)the transportation sector, which taken together will be considerably more difficult than simply extirpating fossil fuel vehicles from the market.

But greening America’s vehicle would be straightforward, relatively cheap, and a huge stride forward on climate. The politics of climate change are so fearful that despair can seem logical, but the first step to achieving a tough goal is the confident belief that it can be done. And this particular step wouldn't even be that tough.

1. How's the goal of keeping global warming below 1.5 degrees Celsius according to Paragraph 1?

A．Reasonable.

B．Safe.

C．Realistic.

D．Impossible.

2. How can electric vehicles compete with fossil-fuel ones?

A．By getting financial support from government.	B．By running at the greatest speed.
C．By changing the way of transportation.	D．By making consumers make logical choices.

3. What should we do to promote electric cars now?

A．Replace as many as gas stations.	B．Solve the problem of long trips.
C．Build more infrastructures for recharging.	D．Make businesses have electrical connections.

4. Which of the following best explains "extirpating" underlined in Paragraph 5?

A．Repairing.

B．Producing.

C．Moving.

D．Forbidding.

【推荐1】Are you preparing for a big test? If so, you may want to play some basketball in between hitting the books. Doctors are starting to find more and more information that suggests a connection between exercise and brain development. Judy Cameron, a scientist at Oregon Health and Science University, studies brain development. According to her research, it seems that exercise can make blood vessels (血管), including those in the brain, stronger and more fully developed. Dr Cameron claims this allows people who exercise to concentrate better. She says, “ While we already know that exercise is good for the heart, exercise can really cause physical changes in the brain.”

The effects of exercise on brain development can even be seen in babies. Babies who do activities that require a lot of movement and physical activity show greater brain development than babies who are less physically active. With babies, even a little movement can show big results. Margaret Barnes, a pediatrician (儿科医生), believes in the importance of exercise. She thinks that many learning disabilities that children have in elementary school or high school can be traced back to a lack of movement as babies. “Babies need movement that stimulates their five senses. They need to establish a connection between motion and memory. In this way, as they get older, children will begin to associate physical activity with higher learning,” says Margaret.

Older people can beef up (加强) their brain as well. Scientists from 11 universities studied a group of seniors ranging in age from 70 to 79. Their study showed a short-term memory increase of up to 40 percent after exercising just three hours a week. The exercise does not have to be very difficult, but it does have to increase the heart rate. Also, just like the motion for babies, exercise for older people should involve some complexity (复杂). Learning some new skills or motions, such as with yoga or tai chi, helps open up memory paths in the brain that may not have used for a long time.

For most people, any type of physical activity that increases the heart rate is helpful. The main goal is to increase the brain’s flow of blood. And your brain can benefit from as little as three hours of exercise a week.

1. The passage is mainly about ________.

A．how to exercise

B．how exercise helps the brain

C．how to get good scores in a test

D．how the brain can change

2. According to the passage, what is the connection between exercise and brain development?

A．Exercise makes us active

B．The brain needs special mental exercise

C．The more exercise, the bigger the brain

D．Physical exercise keeps the brain in a better condition.

3. The least amount of exercise required to gain any benefit is ________.

A．Three hours per week

B．Forty hours per week

C．Three hours per day

D．Forty hours per month

4. Why does the author think that yoga is fit for seniors?

A．It is easy to learn.

B．It can be done in groups.

C．It does not increase the heart rate.

D．It involves learning new motions

【推荐2】Americans: Restless? Illiterate(文盲)？

Americans are queer people; they can’t rest. They have more time, more leisure, shorter work hours, more holidays, and more vacations than any other people in the world. But they can’t rest. They rush up and down across their continent as tourists; they move about in great herds to conventions(大会); they search the wilderness; they flood the mountains; they keep the hotels full. But they can’t rest. The scenery rushes past them. They learn it, but they don’t see it. Battles and monuments are announced to them on a tour bus. They hear them, but they don’t get them. They never stop moving; they rush up and down as Shriners, Masons, Old Graduates, Bankers—they are a new thing each day, always rushing to a reunion or something. So they go on rushing about till eventually the undertaker(殡葬工)gather them to a last convention.

Americans are queer people; they can’t read. They have more schools, and better schools and spend more money on schools and colleges than all Europe. But they can’t read. They print more books in a year than the French print in ten. But they can’t read. They cover their country with one hundred thousand tons of Sunday newspapers every week. But they don’t read them. They’re too busy. They use them for fires and to make more paper with. They buy eagerly thousands of new novels at two dollars each. But they read only page one. Their streets are full of huge signs. They won’t look at them. Their streetcars are filled with advertising; they turn their eyes away. Transparent colors, cart wheels, and mechanical flares whirl and flicker in the crowded streets at night. No one sees them. Tons of letters pour into the mail boxes, through the houses, and down the garbage cans. No one reads them.

1. The underlined word“queer”mean _________________.

A．strange

B．difficult

C．forgetful

D．friendly

2. According to the text, when do the Americans stop rushing about?

A．When they are not allowed to.

B．When they feel tired and sleepy.

C．When they stop breathing eventually.

D．When they are seriously ill in bed.

3. The Americans know the places of battles and monuments ______________.

A．by driving there in person

B．when they are on the tour bus

C．from books and magazines

D．from their friends and co-workers

4. Why does the writer write this passage?

A．To tell people the Americans are illiterate.

B．To prove the Americans to be a queer nation.

C．To make fun of the American way of life.

D．To give the readers information about USA.

【推荐3】Even doctors agree that laughing makes your body and mind feel better. It seems that the act of smiling or laughing sends chemical messages to the brain and affects a person’s mood. Because they feel happier, they feel better. Stress is reduced and anger and tension begin to disappear. Your mind is at peace and so you feel happier and more able to cope with life’s problems.

Laughing and smiling also have the same effect on the body. They improve the body’s ability to stay fit and healthy because the person’s immune system is activated. This means that any germs(病菌) in the body are attacked and killed by these immune system cells. Some doctors even think that skin conditions, such as skin rashes (疹) which may be due to psychological factors, will improve if the person has a good laugh every day. Serious people may not live as long as people who take life less seriously. When you laugh your muscles “contract” (收缩) and relax. This is not the case with very serious people. So a sense of humour is important for a good and healthy life and to remain a fit and strong person you need to laugh and smile for at least ten minutes every day!

1. How can laughter make you feel less pain?

A．By exercising your muscles.	B．By improving your immune system.
C．By producing certain chemicals in your body.	D．By producing new cells.

2. When you laugh, ________.

A．your muscles tighten and then relax	B．you can’t think well and react quickly
C．you can hardly breathe for a while	D．your skin reacts more sensitively

3. What can we conclude from the passage?

A．Laughter can help you live longer.

B．Funny movies can help you with better breathing.

C．Jokes and humour can make you more decisive.

D．People with a good sense of humour don’t get heart disease.