A build-it-yourself solar still (蒸馏器) is one of the best ways to obtain drinking water in areas where the liquid is not readily available. Developed by two doctors in the U.S. Department of Agriculture, it’s an excellent water collector. Unfortunately, you must carry the necessary equipment with you, since it’s all but impossible to find natural substitutes. The only components required, though, are a 5＇ ×5＇ sheet of clear or slightly milky plastic, six feet of plastic tube, and a container — perhaps just a drinking cup — to catch the water. These pieces can be folded into a neat little pack and fastened on your belt.
To construct a working still, use a sharp stick or rock to dig a hole four feet across and three feet deep. Try to make the hole in a damp area to increase the water catcher’s productivity. Place your cup in the deepest part of the hole. Then lay the tube in place so that one end rests all the way in the cup and the rest of the line runs up — and out — the side of the hole.
Next, cover the hole with the plastic sheet, securing the edges of the plastic with dirt and weighting the sheet’s center down with a rock. The plastic should now form a cone (圆锥体) with 45-degree-angled sides. The low point of the sheet must be centered directly over, and no more than three inches above, the cup.
The solar still works by creating a greenhouse under the plastic. Ground water evaporates (蒸发) and collects on the sheet until small drops of water form, run down the material, and fall off into the cup. When the container is full, you can suck the refreshment out through the tube, and won’t have to break down the still every time you need a drink.
What is the last step of constructing a working solar still?
| A．Dig a hole of a certain size. |
| B．Put the cup in place. |
| C．Weight the sheet’s center down. |
| D．Cover the hole with the plastic sheet. |
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【推荐1】Aside from being beautiful and promoting growth, the team observed that due to these lights, they needed to use 50 percent less pesticides (杀虫剂) on the crop. This is because this specific recipe of lights activated the defense system of the plants. And as it works on all crops, not just leeks, Roosegaarde foresees a way to reduce the use of pesticides on many other plants. And his project will soon be touring 40 countries, and sending its dancing lights across the world.
Why are less pesticides needed on the crop with the lights alongside?
| A．The lights make it more resistant to pests. |
| B．The lights kill off most of the pests on it. |
| C．The lights are too bright for pests to tolerate. |
| D．The lights are equipped with a defense system. |
【推荐2】Soft robots, which can move around the ocean without harming sea life, are ideal for underwater exploration. However, they are not so welcome in robot market because they are extremely slow and have a hard time operating through the water. But that may change soon thanks to a self-driven soft robot created by researchers at the University of California, San Diego.
The recently-developed robot, which resembles a paper lantern, was primarily built using soft materials. Its flexible ribs are attached to a circular plate at both ends. An adjustable nozzle (喷嘴) fitted on one side helps draw in and jet (射出) water each time the robot shrinks. The resulting jets of water enable it to swim forward, similar to a squid (乌贼). A plate holds a waterproof component that can house a camera to record data, which is of great value to further development of the robot. It also has its own power source, allowing it to float autonomously for long periods of time.
“Essentially, we recreated all the key features that squids use for high-speed swimming. This is the first robot that can achieve these jets of water by changing its body shape, which improves swimming efficiency,” said Professor Michael T. Though the squid robot has not been tested in open waters, it successfully swam around coral and fish in a large tank in the UC San Diego Birch Aquarium. What’s more, the robot clocked an impressive speed of 18 to 32 centimeters per second, or about half a mile per hour. Though nowhere close to real squids, it is faster than most other soft robots.
“After we were able to improve the design of the robot so that it would swim in a tank in the lab, it was especially exciting to see that the robot was able to successfully swim in a large tank among coral and fish, showing its possibility for real-world applications,” said Caleb Christianson, who led the study as part of his Ph. D paper.
What’s Caleb Christianson’s attitude towards the newly-developed robot?
| A．Positive. | B．Critical. | C．Uncaring. | D．Doubtful. |
【推荐3】During World War II, Hedy’s mother was trapped in Vienna. It was hard for Hedy to help her mother to get to America because every American ship was getting blown up by the Nazis. So she worked on inventing a remote controlled torpedo (鱼雷) so advanced that it would be able to hunt down and blow up every Nazi submarine in the Atlantic, thus securing safe passage to the US. To make sure the Nazis couldn’t detect the radio signal for her torpedo, she created a “secret communication system” that couldn’t be detected.
What led Lamarr to invent a new communication system?
| A．Her passion for science. | B．Her interest in performing. |
| C．Her contract with a studio. | D．Her desire to help her mother out. |
【推荐1】The problem of robocalls has gotten so bad that many people now refuse to pick up calls from numbers they don’t know. By next year, half of the calls we receive will be scams (欺诈). We are finally waking up to the severity of the problem by supporting and developing a group of tools, apps and approaches intended to prevent scammers from getting through. Unfortunately, it’s too little, too late. By the time these “solutions” (解决方案) become widely available, scammers will have moved onto cleverer means. In the near future, it’s not just going to be the number you see on your screen that will be in doubt. Soon you will also question whether the voice you’re hearing is actually real.
How does the author feel about the solutions to problem of robocalls?
| A．Panicked. | B．Confused. | C．Embarrassed. | D．Disappointed. |
【推荐2】Returning to a book you’ve read many times can feel like drinks with an old friend. There’s a welcome familiarity — but also sometimes a slight suspicion that time has changed you both, and thus the relationship. But books don’t change, people do. And that’s what makes the act of rereading so rich and transformative.
The beauty of rereading lies in the idea that our bond with the work is based on our present mental register. It’s true, the older I get, the more I feel time has wings. But with reading, it’s all about the present. It’s about the now and what one contributes to the now, because reading is a give and take between author and reader. Each has to pull their own weight.
Why does the author like rereading?
| A．It evaluates the writer-reader relationship. |
| B．It’s a window to a whole new world. |
| C．It’s a substitute for drinking with a friend. |
| D．It extends the understanding of oneself. |
【推荐3】Just like happiness and sadness, anxiety is part of everyone’s lived experience — but it’s not always tolerated as such. “People often spend too much time and effort trying to rid anxiety,” says Dr Joel Minden, a clinical psychologist. “I encourage them to remember that anxiety is a normal emotional response.”
If you try to banish anxiety, all you’re doing is putting it more at the forefront of your mind. But if you accept anxiety as part of life, you can learn to relate to it with self-pity or even with humour. This is a cornerstone of acceptance and commitment therapy (ACT), which has been gaining clinical validation, including by the American Psychological Association. ACT guides people to see their unpleasant emotions as just feelings and to accept that parts of life are hard. Sufferers are encouraged to begin a dialogue with anxious thoughts, examining their causes while also keeping in mind their personal goals and values.
......
What may Dr Joel Minden agree about anxiety?| A．It is often improperly treated. | B．It should be seriously taken. |
| C．It is easily-earned experience. | D．It goes hand in hand with joy. |
【推荐1】Love is one of life’s greatest motivators. That is exactly what inspired Zack to design a fully electric off-road wheelchair for his girlfriend suffering from paralysis (瘫痪).
Like most wheelchair-users, Cambry has always been restricted to the pavement for most of her adult life. Aside from that, using a wheelchair across long distances makes her shoulders ache. Zack Nelson, her boyfriend, wanted to give her the ability to explore more places conveniently, so he made a special wheelchair for her, which would make it possible.
Zack began by combining two electric bikes and installing a seat in the centre. It worked! Cambry experienced a whole new level of freedom using her new “ride”, and she couldn’t be more grateful to Zack for coming up with it. Fast forward to a year later, Cambry and Zack tied the knot. They also began mass-production of the special wheelchair. Throughout that time, they improved the original design to make it a more reliable off-roader.
While similar vehicles already exist in the market, they said they’re either slow or cost as much as a car. Cambry and Zack wanted to build something quick, light, super long-range, and affordable at the same time. However, coming up with that kind of electric off-roader wasn’t easy.
The toughest challenge when developing the special wheelchair is the price. “We wanted to create something that is affordable for everyone. Finding quality components, and a simple enough design at the cheapest price possibly took quite a bit of time,” said Zack. “But I think we have something now that everyone will be able to enjoy, at a fraction (少量) of the cost of other ‘off-road wheelchairs’ currently on the market.” Another great thing about the vehicle is that it’s silent. Its rider will have no difficulty chatting with their companion while using it. Cambry and Zack are very happy with the fully-electric machine, and they hope that other wheelchair-users will also benefit from it.
What was Zack’s motivation to invent a fully electric wheelchair?| A．The market demands. |
| B．His interest in invention. |
| C．His love for his girlfriend. |
| D．The request of his girlfriend. |
【推荐2】In 1934, with the passage of the Migratory Bird Hunting Stamp Act (Act), an increasingly concerned nation took firm action to stop the destruction of migratory ( 迁徙的) waterfowl and the wetlands so vital to their survival. Under this Act, all waterfowl hunters 16 years of age and over must annually purchase and carry a Federal Duck Stamp. The very first Federal Duck Stamp was designed by J.N. “Ding” Darling, a political cartoonist from Des Moines, lowa, who at that time was appointed by President Franklin Roosevelt as Director of the Bureau of Biological Survey. Hunters willingly pay the stamp price to ensure the survival of our natural resources.
About 98 cents of every duck stamp dollar goes directly into the Migratory Bird Conservation Fund to purchase wetlands and wildlife habitat for inclusion into the National Wildlife Refuge System — a fact that ensures this land will be protected and available for all generations to come. Since 1934
better than half a billion dollars has gone into that Fund to purchase more than 5 million acres of habitat. Little wonder the Federal Duck Stamp Program has been called one of the most successful conservation programs ever initiated.
What is a direct result of the Act passed in 1934?
| A．The stamp price has gone down. |
| B．The migratory birds have flown away. |
| C．The hunters have stopped hunting. |
| D．The government has collected money. |
Plants can also detect volatile compounds produced by other plants. A tree under attack by Hungry insets, for instance, may give off volatile compounds that let other trees know about the Attack. In response, the other trees may send off chemicals to keep the bugs away ——or even Chemicals that attract the bugs’ natural enemies.
Now scientists have created a quick way to understand what plants are saying: a chemical Sensor（传感器）called an electronic nose. The “e-nose” can tell compounds that crop plants make When they’re attacked Scientists say the e-nose could help quickly detect whether plants are being Eaten by insects. But today the only way to detect such insects is to visually inspect individual Plants. This is a challenging task for managers of greenhouses, enclosed gardens than can house Thousands of plants.
The research team worked with an e-nose than recognizes volatile compounds. Inside the device, 13 sensors chemically react with volatile compounds Based on these interactions, the e-nose gives off electronic signals that the scientists analyze using computer software.
To test the nose, the team presented it with healthy leaves from cucumber, pepper and tomato plants, all common greenhouse crops. Then scientists collected samples of air around damaged leaves from each type of crop, These plants had been damaged by insects, or by scientists who made holes in the leaves with a hole punch（打孔器）. The e-nose, it turns out, could identify healthy cucumber, pepper and tomato plants based on The volatile compounds they produce, It could also identify tomato leaves that had been damaged. But even more impressive, the device could tell which type of damage ---- by insects or with a hole Punch ---- had been done to the tomato leaves.
With some fine-tuning, a device like the e-nose could one day be used in greenhouses to quickly spot harmful bugs, the researchers say. A device like this could also be used to identify fruits that are perfectly ripe and ready to pick and eat, says Natalia Dudareva, a biochemist at Purdue University in West Lafayette, Ind. who studies smells of flowers and plants. Hopefully, scientists believe, the device could bring large benefits to greenhouse managers in the near future.
1. We learn from the text that plants communicate with each other by____.
| A．making some sounds | B．waving their leaves |
| C．producing some chemicals | D．sending out electronic signals |
| A．They presented it with all common crops. |
| B．They fixed 13 sensors inside the device. |
| C．They collected different damaged leaves. |
| D．They made tests on damaged and healthy leaves. |
| A．pick out ripe fruits |
| B．spot the insects quickly |
| C．distinguish different damages to the leaves |
| D．recognize unhealthy tomato leaves |
| A．is unable to tell the smell of flowers |
| B．is not yet used in greenhouses |
| C．is designed by scientists at Purdue |
| D．is helpful in killing harmful insects |
