Diets have changed in China — and so too has its top crop. Since 2011, the country     1    （grow）more corn than rice. Corn production has jumped nearly 125 percent over     2     past 25 years, while rice has increased only 7 percent.

A taste for meat is     3     (actual) behind the change: An important part of its corn is used to feed chickens, pigs, and cattle. Another reason for corn's rise: The government encourages farmers to grow corn instead of rice     4     (improve) water quality. Corn uses less water     5     rice and creates less fertilizer(化肥) runoff. This switch has decreased     6     (pollute) in the country's major lakes and reservoirs and made drinking water safer for people.

According to the World Bank, China accounts for about 30 percent of total     7     (globe)fertilizer consumption. The Chinese Ministry of Agriculture finds that between 2005—when the government     8     (start) a soil-testing program     9     gives specific fertilizer recommendations to farmers - and 2011, fertilizer use dropped by 7.7 million tons. That prevented the emission(排放) of 51.8 million tons of carbon dioxide. China's approach to protecting its environment while     10     (feed) its citizens "offers useful lessons for agriculture and food policymakers worldwide." says the bank's Juergen Voegele.

3 . Washington, D.C. Bicycle Tours

Cherry Blossom Bike Tour in Washington, D.C.

Duration: 3 hours

This small group bike tour is a fantastic way to see a world-famous cherry trees with beautiful flowers of Washington, D.C. Your guide will provide a history lesson about the trees and the famous monuments where they blossom. Reserve your spot before availability — the cherry blossoms—disappear!

Washington Capital Monuments Bicycle Tour

Duration: 3 hours (4 miles)

Join a guided bike tour and view some of the most popular monuments in Washington, D.C. Explore the monuments and memorials on the National Mall as your guide shares unique facts and history at each stop. Guided tour includes bike, helmet, cookies and bottled water.

Capital City Bike Tour In Washington, D.C.

Duration: 3 hours

Morning or Afternoon, this bike tour is the perfect tour for D. C. newcomers and locals looking to experience Washington, D.C. in a healthy way with minimum effort. Knowledgeable guides will entertain you with the most, interesting stories about Presidents, Congress, memorials, and parks. Comfortable bikes and a smooth tour route(路线) make cycling between the sites fun and relaxing.

Washington Capital Sites at Night Bicycle Tour

Duration: 3 hours (7miles)

Join a small group bike tour for an evening of exploration in the heart of Washington, D.C. Get up close to the monuments and memorials as you bike the sites of Capitol Hill and the National Mall. Frequent stops are made for photo taking as your guide offers unique facts and history. Tour includes bike, helmet, and bottled water. All riders are equipped with reflective vests and safety lights.

5 . We may think we're a culture that gets rid of our worn technology at the first sight of something shiny and new, but a new study shows that we keep using our old devices(装置) well after they go out of style. That’s bad news for the environment — and our wallets — as these outdated devices consume much more energy than the newer ones that do the same things.

To figure out how much power these devices are using, Callie Babbitt and her colleagues at the Rochester Institute of Technology in New York tracked the environmental costs for each product throughout its life — from when its minerals are mined to when we stop using the device. This method provided a readout for how home energy use has evolved since the early 1990s. Devices were grouped by generation — Desktop computers, basic mobile phones, and box-set TVs defined 1992. Digital cameras arrived on the scene in 1997. And MP3 players, smart phones, and LCD TVs entered homes in 2002, before tablets and e-readers showed up in 2007.

As we accumulated more devices, however, we didn't throw out our old ones. "The living-room television is replaced and gets planted in the kids' room, and suddenly one day, you have a TV in every room of the house," said one researcher. The average number of electronic devices rose from four per household in 1992 to 13 in 2007. We're not just keeping these old devices — we continue to use them. According to the analysis of Babbitt's team, old desktop monitors and box TVs with cathode ray tubes are the worst devices with their energy consumption and contribution to greenhouse gas emissions（排放）more than doubling during the 1992 to 2007 window.

So what's the solution（解决方案）? The team's data only went up to 2007, but the researchers also explored what would happen if consumers replaced old products with new electronics that serve more than one function, such as a tablet for word processing and TV viewing. They found that more on-demand entertainment viewing on tablets instead of TVs and desktop computers could cut energy consumption by 44%.

6 . When “Rise of the Planet of the Apes” was first shown to the public last month, a group of excited animal activists gathered on Hollywood Boulevard. But they weren’t there to throw red paint on fur-coat-wearing film stars. Instead, one activist, dressed in a full-body monkey suit, had arrived with a sign praising the filmmakers: “Thanks for not using real apes (猿)!”

The creative team behind “Apes” used motion-capture (动作捕捉) technology to create digitalized animals, spending tens of millions of dollars on technology that records an actor’s performance and later processes it with computer graphics to create a final image (图像). In this case, one of a realistic-looking ape.

Yet “Apes” is more exception than the rule. In fact, Hollywood has been hot on live animals lately. One nonprofit organization, which monitors the treatment of animals in filmed entertainment, is keeping tabs on more than 2,000 productions this year. Already, a number of films, including “Water for Elephants,” “The Hangover Part Ⅱ” and “Zookeeper,” have drawn the anger of activists who say the creatures acting in them haven’t been treated properly.

In some cases, it’s not so much the treatment of the animals on set in the studio that has activists worried; it’s the off-set training and living conditions that are raising concerns. And there are questions about the films made outside the States, which sometimes are not monitored as closely as productions filmed in the States.

“I'm going to miss you so much, Poppy, "said the tall, thin teenager. He bent down to hug his old friend goodbye. He stood up, hugged his parents, and smiled, trying not to let his emotions(情绪)get the better of him.

His parents were not quite able to keep theirs under control. They had driven their son several hours out of town to the university where he would soon be living and studying. It was time to say goodbye for now at least. The family hugged and smiled through misty eyes and then laughed.

The boy lifted the last bag onto his shoulder, and flashed a bright smile.” I guess this is it, “he said.” I'll see you back home in a month, okay？"His parents nodded, and they watched as he walked out of sight into the crowds of hundreds of students and parents. The boy's mother turned to the dog, “Okay, Poppy, time to go back home.”

The house seemed quiet as a tomb without the boy living there. All that week, Poppy didn't seem interested in her dinner, her favorite toy, or even in her daily walk. Her owners were sad too, but they knew their son would be back to visit. Poppy didn't.

They offered the dog some of her favorite peanut butter treats. They even let her sit on the sofa, but the old girl just wasn't her usual cheerful self. Her owners started to get worried. "What should we do to cheer Poppy up？"asked Dad. “We've tried everything.”

“I have an idea, but it might be a little crazy, “smiled Mom.” Without anybody left in the house but us, this place could use a bit of fun. Let's get a little dog for Poppy."

It didn't take long before they walked through the front door carrying a big box. Poppy welcomed them home as usual, but when she saw the box, she stopped. She put her nose on it. Her tail began wagging(摆动)ever so slowly, then faster as she caught the smell.

8 . The Upside to Being Outside

Research shows that being in nature makes people feel good, whether they’re roughing it in the wilderness for days or just hanging out at a local park for a while. One study was conducted in the city of Birmingham, Alabama. Researchers found that most participants’ mood and well-being improved significantly when they spent time in urban parks, even though the average visit was only around half an hour.

    1     For example, scientists in the United Kingdom studied the impact of the “30 Days Wild” campaign. It challenged people to interact with nature for 30 days by enjoying earthy activities like feeding birds and planting flowers. Participants were measurably happier and healthier throughout the challenge…and for months afterwards, too.    2    

How does nature boost people’s happiness? Scientists say that spending time in natural settings reduces stress and anxiety, which benefits mental and physical health. Research shows our brains are more relaxed in natural settings.

To most people, it’s not news that nature can be calming. But multiple studies have found that spending time in nature also has some more surprising benefits, like improving creativity and problem-solving.     3     Another found that exposure to nature helped people score better on tests. That’s more proof that going outside is a smart move!

What accounts for the connection with cognition and creativity? It could be that a good dose of nature acts as a cure to information overload. Everyday life involves a lot of multitasking. Some scientists theorize that spending time in nature enables our brains to rest and recover from mental tiredness.     4    

Naturally, scientific studies don’t cover everything that’s great about the great outdoors.     5     From recreation and exercise to happiness and creativity, there are lots of upsides to getting outside.

9 . Monkeys seem to have a way with numbers.

A team of researchers trained three Rhesus monkeys to associate 26 clearly different symbols consisting of numbers and selective letters with 0-25 drops of water or juice as a reward. The researchers then tested how the monkeys combined—or added—the symbols to get the reward.

Here’s how Harvard Medical School scientist Margaret Livingstone, who led the team, described the experiment: In their cages the monkeys were provided with touch screens. On one part of the screen, a symbol would appear, and on the other side two symbols inside a circle were shown. For example, the number 7 would flash on one side of the screen and the other end would have 9 and 8. If the monkeys touched the left side of the screen they would be rewarded with seven drops of water or juice; if they went for the circle, they would be rewarded with the sum of the numbers—17 in this example.

After running hundreds of tests, the researchers noted that the monkeys would go for the higher values more than half the time, indicating that they were performing a calculation, not just memorizing the value of each combination.

When the team examined the results of the experiment more closely, they noticed that the monkeys tended to underestimate(低估) a sum compared with a single symbol when the two were close in value—sometimes choosing, for example, a 13 over the sum of 8 and 6. The underestimation was systematic: When adding two numbers, the monkeys always paid attention to the larger of the two, and then added only a fraction(小部分) of the smaller number to it.

“This indicates that there is a certain way quantity is represented in their brains, ”Dr. Livingstone says. “But in this experiment what they’re doing is paying more attention to the big number than the little one.”

I'm not sure     1     is more frightened, me or the female gorilla(大猩猩）that suddenly appears out of nowhere. I'm walking on a path in the forest in the Central African Republic. Unexpectedly, I'm face-to-face with the gorilla, who begins screaming at     2     top of her lungs. That makes her baby scream, and then a 400-pound male appears. He screams the

    3    (loud)of all. The noise shakes the trees as the male beats his chest and charges toward me. I quickly lower myself, ducking my head to avoid     4    (look) directly into his eyes so he doesn't feel    5    (challenge).

My name is Mireya Mayor. I'm a     6    (science)who studies animals such as apes and monkeys. I was searching     7     these three western lowland gorillas I'd been observing. No one had seen them for hours, and my colleagues and I were worried.

When the gorillas and I frightened each other, I was just glad to find     8    (they) alive. True to a gorilla's unaggressive nature, the huge animal     9    (mean)me no real harm. He was just saying: "I'm king of this forest, and here is your reminder!" Once his message was delivered, he allowed me     10     (stay)and watch.