1 . Most solar panels acquire sunlight from only one side, meaning they can acquire more or less of it depending on where the sun is in the sky. In recent years, they’ve become far more effective typically turning around 22 percent of the light they acquire into energy. In a new study published in the journal Joule on Tuesday, scientists put forth a way to increase that percentage even higher: double-sided solar panels that can move to follow the sun.
Basically, these panels can acquire sun from not only their sun-facing side but also from the light reflected off the ground onto their dark undersides. At the same time, a GPS allows them to move on an axis from east to west in order to always be pointed at a best angle to acquire the sun’s rays. Though double-sided solar panels and sun-following solar panels are both in use currently, models that combine the two technologies aren’t widely available for commercial use, Solar experts predict explosive growth in the market soon, though.
The study authors determined that these two-sided sun-tracking panels produce an average of 35 percent more energy than immobile single-panel systems, and are 16 percent more cost-efficient. That holds true even when accounting for changes in weather conditions.
“This means that investing in double-sided and tracking systems should be a safe bet for the foreseeable future, Carlos Rodriguez-Gallegos,” the study’s lead author said.
The same warnings for solar panels and their effect on the local environment apply to the double-sided, moving systems as well, if not more so. Lead used in solar panels can be one source of local pollution, and Dustin Mulvaney, an associate professor of environmental studies, told Earther in an email double-sided panels could mean “twice as much lead” as traditional solar systems.
Since these new panels are more energy efficient, they could save not only money but also land. That would require restructuring how solar contracts currently work.
1. What does most solar panels rely on to acquire sunlight?| A．The amount of sunlight. | B．The location of the sun. |
| C．The quality of solar panels. | D．The size of solar panels. |
| A．The sun’s rays. | B．The panels’ undersides. |
| C．The double-sided panels | D．The panels’ sun-facing sides. |
| A．Uncertain. | B．Supportive. | C．Doubtful. | D．Subjective. |
| A．Double-Sided Solar Panels that Follow the Sun | B．Advantages of the Double-Sided Solar Panels |
| C．Application of the Double-Sided Solar Panels | D．New Trends of Double-Sided Solar Panels |
2 . Have you ever loved a destination but couldn’t figure out why — or even a way ——to express your feelings? That’s my dilemma with Morocco.
In August, I traveled in a country that had long been, on my wish list. I rode a camel, got lost in Medinas, and ate more couscous (粗麦粉) than was humanly possible.
I loved the trip. Our friendly guide introduced us to the helpful locals. I made friends with my tour mates and my roommate (which, on a tour, is a huge blessing). I loved being lost in the smell of different spices, and the chaos of millions of people and the dark red of the Sahara were all I wanted them to be.
There were many moments when I felt like a fish out of water and things didn’t go my way. But I take pleasure in those moments because it’s when you are pushed out of your comfort zone that you grow. Morocco lived up to all my expectations, but for some reason, my experience has been hard to express. Why?
One constant in my travels is that of a touchstone, one defining point where the trip all comes together and acts as a prism (三棱镜) for everything the journey represented . In Costa Rica，it was getting lost in a jungle. In Thailand, it was meeting those five people who changed my life.
I’m so inconsistent about Morocco because I lack that touchstone. There’s no “whoa” moment. But I have thousands of little ones - staring at a million stars in the blackness of the desert, discovering new foods with some amazing Australians on my tour, and befriending the fish sellers.
1. What does the author regard as a huge blessing?| A．Going on a guided trip. |
| B．Having a helpful guide. |
| C．Being warmly received by the local people. |
| D．Getting along well with the fellow travelers. |
| A．To prove Morocco lacks the touchstone. |
| B．To show his reliance on the touchstone. |
| C．To compare Morocco with Costa Rica and Thailand. |
| D．To share his experience in Costa Rica and Thailand. |
| A．The lack of big moments. |
| B．The little “whoa” moments. |
| C．Meeting with five Thai people. |
| D．Making friends with Australians. |
| A．Unpleasant travel in Morocco. |
| B．Finding a touchstone on travel. |
| C．Reflection on traveling in Morocco. |
| D．Lack of special moments in Morocco. |
3 . Why did the little boy throw butter out of the window? He wanted to see the butterfly! That’s an old joke you’ve probably heard many times. Butterflies always carry away children.
Most insects do not migrate(迁徙), because their life is not long enough. Except for one particular butterfly species-the monarch butterfly. Each November, monarch butterflies land on an unbelievable cross-country migration from the United States and Canada until they reach Mexico, where they overwinter until it’s time to begin their migration back home in March. The butterflies spend their time in concentrated areas of forest where they stick to the branches of trees, forming beautiful vast crowds. Monarchs are a truly important species-and they’re in danger.
Just like living things, plants, insects or animals on the planet, monarchs play a vital role in the survival of our ecosystems. Butterflies-just like bees, also in great danger-help pollinate(授粉) plants, making them a significant contributor to crop growth and food production. They also serve as a food source to birds and other animals. The population of monarch butterflies has dropped a lot over the past few decades—a destructive 96. 5 percent. This has placed monarchs in danger of moving toward dying out. Several causes have contributed to the monarch’s decline. Climate change, loss of reproductive homes, and deforestation in Mexico’s forests where monarchs overwinter have all affected the butterfly’s migration pattern and home. But the most significant danger is the decline in milkweed, the plant where monarchs lay their eggs, and that serves as the only food source for caterpillars(幼虫). Much of the milkweed decline is due to agricultural practices that either remove this vital plant or destroy it through pesticides(农药).
1. Why do monarch butterflies move to Mexico?| A．To survive the cold weather. | B．To escape from being hunted. |
| C．To take advantage of the flowers there. | D．To cooperate with the bees there. |
| A．They help birds to catch their food. | B．They produce seeds for wild plants. |
| C．They contribute to crop production. | D．They bring food to other animals. |
| A．Monarch Butterflies Migrate | B．Butterflies Attract Children |
| C．Fight to Save Monarch Butterflies | D．Monarch Butterflies Are in Danger |
| A．Why monarch butterflies decline. |
| B．How monarch butterflies can be saved. |
| C．How monarch butterflies reproduce. |
| D．Why monarch butterflies migrate. |
4 . If you've been dreaming of having an electric car, but can't yet afford to buy one, you can start at a low price, really low. Changli, the world's cheapest electric car, can be ordered online and sent to your door for just $ 930.
Designed and produced by Chinese maker Changzhou Xili Car Industry, Changli, and Changli Nemeca is a small electric car that has got lots of attention online after being advertised as the world's most affordable electric car. Calling this thing a car is kind of stretching it a bit, as its electric motor can only produce 1.16 horsepower, and it has a top speed of only 30. km/h. Still, it does come with some interesting features, like air-conditioning, independent suspension, heater, radio and even reverse-view camera. But the most impressive thing about Changli in my opinion, is that you can have it sent to your doorstep.
Anyone who can just order Changli Nemeca online can have it mailed to them without having to pay extra money to the dealership. Changli measures 2.5 meters long, 1.5 meter wide, and 1.8 meters high, weighs 323 kilograms and can carry up to 30 kilograms.
The two-seat version starts at $ 930($ 1,200 with larger batteries), but you can choose a three-seat version as well, which will cost you $ 1,50. The battery of the small electric car is between 40 and 10 kilometers per charge and the batteries take between 7 and 10 hours to charge.
While Changli Nemeca won't be going head to head with other electric cars anytime soon it's still an amazing piece of machinery for the price. Where else are you going to find full functional electric cars that you can have mailed to your door.
1. Why does the author think Changli electric car is the most impressive?| A．Because of its design. | B．Because it's convenient. |
| C．Because it's light and cheap. | D．Because of its appearance. |
| A．Its producer. | B．Its users. | C．Its production. | D．Its features. |
| A．By making comparisons. | B．By listing numbers. |
| C．By giving examples. | D．By reasoning. |
| A．Optimistic. | B．Pessimistic. | C．Uncertain. | D．Hopeless. |
5 . Traffic jams are the horrible dreams of motorists’ lives. If you think your journey is bad, spare a thought for drivers in Sao Paolo, Brazil — one evening in May last year, the traffic jams during the rush hour added up to a 344km queue, according to the city's traffic management agency.
This isn't a new problem, of course. During the car boom of the 1960s, city planners had one seemingly obvious solution: build more and wider roads. But the more roads created, the more cars they attracted. So what's the solution? Some cities have adopted easy methods, like banning cars from driving on certain days.
However, ending this horrible dream may need more of a complete rethink. A company, Urban Engines, has a slightly fresher method. "We're providing an online game that offers trip suggestions and prizes to encourage commuter behaviour changes, including changing travel from peak to off-peak times,“ says Shiva Shivakumar, Urban Engines' co-founder and GEO. For the past two-and-a-half years, the company has conducted pilot studies in major cities, including Bangalore and Singapore. In Bangalore, one-in-six people who took part in the trial started travelling off-peak, and in Singapore one-in-eight.
But others think this solution doesn't go far enough—and that we should provide more reasons for putting fewer cars on the road. “The only effective long-term solution is to improve alternative methods—walking, cycling and particularly high-quality public transport,” says Todd Litman of the Victoria Transport Policy Institute in Canada. Road pricing that charges motorists extra if they drive during the rush hour could also be an option. Cities like Singapore, London and Stockholm have successfully used road pricing to control the steel river.
The solution to beating traffic jams in cities, if it comes, will probably take a long time to gain prizes. But if at least some of these new ideas are a success, the days of Sao Paolo's heavy traffic jams may finally become history.
1. What can we learn about the method of building wider roads?| A．It results in the car boom. | B．It is far from satisfactory. |
| C．It needs to be further tested. | D．It is unlikely to be widely used. |
| A．It charges commuters for travelling at peak times. |
| B．It changes its working time to avoid peak times. |
| C．It bans commuters from driving on certain days. |
| D．It offers prizes to those travelling at off-peak times. |
| A．The traffic flow. | B．The traffic light. |
| C．The public transport. | D．The crowd of people. |
| A．How Do Traffic Jams Form | B．Can We Ever End Traffic Jams |
| C．Do Traffic Jams Affect Our Life | D．Where Is the Most Jammed City |
