Coffee drink is widespread. When people argue about whether coffee is good for health, they're usually thinking of the health of the coffee drinker. Is it good for your heart? Does it increase blood pressure? Does it help you concentrate? However, coffee affects the health of the human population in other ways, too.

    Traditionally, coffee bushes were planted under the shade of taller trees. However, more and more farmers in Latin America are deforesting the land to grow full sun coffees. At first, this increases production because more coffee bushes can be planted if there aren't any trees. With increased production come increased profits.

    Unfortunately, deforesting for coffee production immediately decreases the local wildlife habitat, because native birds nest and hide from predators（捕食者）in the tall trees and migrating birds rest there.

    Furthermore, in the long term, the full-sun method also damages the ecosystem because more chemical fertilizers and pesticides（杀虫剂）are needed to grow the coffee. The fertilizers and pesticides kill insects that eat coffee plant, and then the birds eat the poisoned insects and also die. The chemicals kill or sicken other animals as well, and can even enter the water that people will eventually drink.

    Fortunately, farmers in Central and South America are beginning to grow more coffee bushes in the shade. We can support these farmers by buying coffee with such labels as "shade-grown" and "bird-friendly".

    Sure, these varieties might cost a little more. But we're paying for the health of the birds, the land, ourselves, and the planet. I think it's worth it.

    By the mid-nineteenth century, the term “icebox” had entered the American language, but ice was still only beginning to affect the diet of ordinary citizens in the United States. The ice trade grew with the growth of cities. Ice was used in hotels, pubs, and hospitals, and by some forward-looking city dealers in fresh meat, fresh fish, and butler. After the Civil War (1861-1865), as ice was used to refrigerate freight cars(货车), it also came into household use. Even before 1880, half the ice sold in New York, Philadelphia, and Baltimore, and one-third of that sold in Boston and Chicago, went to families for their own use. This had become possible because a new household convenience, the icebox, a precursor（前身）of the modem refrigerator, had been invented.

    Making an efficient icebox was not as easy as we might now suppose. In the early nineteenth century, the knowledge of the physics of heat, which was essential to a science of refrigeration, was undeveloped. The common belief that the best icebox was one that prevented the ice from melting was of course mistaken, for it was the melting of the ice that performed the cooling. Nevertheless, early efforts to economize ice included wrapping the ice in blankets, which kept the ice from doing its job. Not until near the end of the nineteenth century did inventors achieve the delicate balance of insulation(绝缘) and circulation needed for an efficient icebox.

    But as early as 1803, an intelligent Maryland farmer, Thomas Moore, had been on the right track. He owned a farm about twenty miles outside the city of Washington, for which the village of Georgetown was the market center. When he used an icebox of his own design to transport his butter to market, he found that customers would pass up the rapidly melting butter of his competitors to pay an extra price for his butter, still fresh and hard in neat, one-pound bricks. One advantage of his icebox, Moore explained, was that fanners would no longer have to travel to market at night in order to keep their produce cool.

    Mother Teresa was born on August 26th,1910 in Skopje, Macedonia. She always wrote her birthday as 27th of August because it was the day of her baptism(洗礼), which was always more important to her than her birthday. For her work with the poor around the world, she received the 1979 Nobel Peace Prize.

    In 1928, she accepted a religious order and took the name Teresa. The order immediately sent her to India. A few years later, she began teaching in Calcutta. In 1948 the Catholic(天主教的) Church agreed her request and let her enter the convent( 女修道院) and she began to work for the poor people. She became an Indian citizen in the following year. In 1950, she set up a religious organization in Calcutta. The organization provided food for the poor people and then she set up hospitals, schools, youth centers, and homes for the sick and the dying poor. It now has branches in 50 Indian cities and 30 other countries.

    Besides the 1979 Nobel Peace Prize, Mother Teresa has received other awards for her work with the poor people. On September 5th,1997, Mother Teresa passed away, but she will continue to inspire people all over the world through her lasting present of love and faith.

    The month of March was a milestone for supporters of renewable energy in the U.S. For the first time, wind and solar power accounted for more than 10% of the country's electricity—up from less than 1% at the turn of the century. And total wind and solar power-plant capacity(发电量) is expected to grow more than 30% over the course of this year and next, according to the Energy Information Administration.

    Such forecasts have led many scientists and policymakers to think that moving a large part of the nation's power supply to renewable sources—as cities from Miami Beach to Salt Lake City have promised to do—may not be as far-fetched as once thought. But like any debate, there are dissenters, including those inside the federal government. Their argument is that the nation demands an uninterrupted supply of electricity and cannot count on sun, wind and natural gas to provide it. “You need solid hydrocarbons(固体碳氢化合物) on-site for rising peak demand,” Environmental Protection Agency administrator Scott Pruitt said on Fox Business in May, referring to the importance of coal as a power source.

    Many experts say the government's concern fails to account for how the power grid(电网) has improved in recent decades. Utility companies(公共事业公司) have developed innovative ways to move electricity from place to place to account for variation in weather. Battery technology can store power for use when renewable sources cannot operate, meaning solar power can be used on days when the sun doesn't shine. And the nation's vast supply of natural gas can be turned into usable energy with the flick of a switch.

    “I don't think 5 or 10 years ago I'd be comfortable telling you we could not sacrifice reliability when we're going to have 35% of our energy come from wind,” said Ben Fowke, CEO of the utility company Xcel Energy, at a recent conference. “I'm telling you, I'm very comfortable with that today.”

    Indeed, many parts of the country are already close to that reality. In some regions, like Iowa and Kansas, renewable energy supplies more than 25% of the electricity. The market has shifted so far in favor of natural gas and renewable energy that even the most concerted federal effort is unlikely to stop its growth. Any attempt to slow the growth of wind and solar will face strong pushback. “If anyone wants to do away with it,” Republican Senator Chuck Grassley told Yahoo News of the federal government's potential cuts to wind energy, “he'll do it over my dead body.”

    But the federal government could slow the acceleration—and with billions of dollars in private and public investments at risk, the pace of change matters. Decisions made today will shape the future of the nation's energy grid for decades to come.

    About twenty of us had been fortunate enough to receive invitations to a film­studio (影棚) to take part in a crowd­scene. Although our “act” would last only for a short time，we could see quite a number of interesting things.

    We all stood at the far end of the studio as workmen prepared the scene，setting up trees at the edge of a winding path. Very soon, bright lights were turned on and the big movie­camera was wheeled into position. The director shouted something to the camera operator and then went to speak to the two famous actors nearby. Since it was hot in the studio, it came as a surprise to us to see one of the actors put on a heavy overcoat and start walking along the path. A big fan began blowing tiny white feathers down on him, and soon the trees were covered in “snow”. Two more fans were turned on，and a “strong wind” blew through the trees. The picture looked so real that it made us feel cold.

    The next scene was a complete contrast (对比). The way it was filmed was quite unusual. Pictures taken on an island in the Pacific were shown on a glass screen (幕). An actor and actress stood in front of the scene so that they looked as if they were at the water's edge on an island. By a simple trick like this, palm trees, sandy beaches, and blue, clear skies had been brought into the studio!

    Since it was our turn next，we were left wondering what scene would be prepared for us. For a full three minutes in our lives we would be experiencing the excitement of being film “stars”！

    You can relax if remembering everything isn't your strong suit. Recent research makes the case that being forgetful can be a strength—in fact, selective memory can even be a sign of stronger intelligence.

    Traditional research on memory has focused on the advantages of remembering everything. But looking through years of recent memory data, researchers found that the neurobiology of forgetting can be just as important to our decision-making as what our minds choose to remember.

    Making intelligent decisions doesn't mean you need to have all the information at hand. It just means you need to hold onto the most valuable information. And that means clearing up space in your memory palace for the most up-to-date information on clients and situations. Our brains do this by creating new neurons(神经元）in our  hippocampus, which have the power to overwrite(重写)existing memories that are influencing our decision-making.

    If you want to increase the number of new neurons in our brain's learning region, try exercising. Some aerobic exercise like jogging, power walking and swimming has been found to increase the number of neurons making important connections in our brains.

    When we forget the names of certain clients or details about old jobs，the brain is making a choice that these details don't matter. Although too much forgetfulness can be a cause for concern, the occasional lost detail can be a sign of a perfectly healthy memory system. The researchers found that our brains facilitate decision-making by stopping us from focusing too much on unimportant past details. Instead，the brain helps us remember the most important part of a conversation.

    We can get blamed for being absent-minded when we forget past events in perfect detail. These findings show us that total recall(记忆)can be overvalued. Our brains are working smarter when they aim to remember the right stories, not every story.