Do you know how it is when you see someone yawn and you start yawning too? Or how hard it is to be among people laughing and not laugh yourself? Well, apparently it's because we have mirror neurons (神经元）in our brains.

    Put simply, the existence of mirror neurons suggests that every time we see someone else do something, our brains imitate (模仿)it，whether or not we actually perform the same action. This explains a great deal about how we learn to smile, talk, walk, dance or play sports. But the idea goes further： mirror neurons not only appear to explain physical actions _y they also tell us that there is a biological basis for the way we understand other people.

    Mirror neurons can undoubtedly be found all over our brains, but especially in the areas which relate to our ability to use languages, and to understand how other people feel. Researchers have found that mirror neurons relate strongly to language. A group of researchers discovered that if they gave people sentences to listen to ( for example ："The hand took hold of the ball" ) , the same mirror neurons were triggered as when the action was actually performed (in this example, actually taking hold of a ball).

    Any problems with mirror neurons may well result in problems with behavior. Much researeh suggests that people with social and behavioral problems have mirror neurons which are not fully functioning. However, it is not yet known exactly how these discoveries might help find treatments for social disorders.

    Research into mirror neurons seems to provide us with ever more information concerning how humans behave and interact(互动）.Indeed, it may turn out to be the equivalent (相等物）for ncurosciencc of what Einstein's theory of relativity was for physics. And the next time you feel the urge to cough in the cinema when someone else does--well，perhaps you'll understand why.

    Hidden from the noise of Washington, D.C., Hillwood Museum is a special treasure. It contains (包含) one of the finest personal collections (收藏) of Russian and French art in the world.

    Hillwood Museum was once the home of Marjorie Merriweather Post. She was a rich businesswoman. She owned one of the largest food companies in the United States. She was also very interested in collecting beautiful French art and furniture.

    She moved to Russia in the 1930s as her third husband, Joseph Davies, became the American ambassador (大使) in Moscow. Marjorie Merriweather Post had a love for Russian art as well. She bought the house in Washington in 1955 and she wanted to make it into a museum after her death. Many art experts helped Mrs. Post create its fine collection.

    Hillwood has many rooms which are filled with her treasures. Visitors can see beautiful music boxes from the eighteenth century and colorful paintings of European princesses (公主). Experts say the ancient wood and gold furniture from France is some of the finest ever made. Visitors can even look at Mrs. Post's jewels and clothes.

    The museum also has several beautiful gardens. One is designed like the gardens in Japan. It has a bridge and visitors can watch flowers floating in the water. Flowers are also grown all the year in a special glass building or greenhouse. These flowers are placed in the house throughout the year.

After a walk, visitors can rest at a nearby eating place. They can also buy objects to remember this special museum.

    With the wide, application of the Internet, Uber, a new approach to your destination instead of taking an ordinary taxi, has become more popular recently. However, benefits won't come without its fair share of drawbacks. The ride-sharing experience is about to get awkward.

    Uber drivers are a part of the so-called sharing economy: They use their own vehicles, receive customer reviews via the app's five-star rating system and make their own hours and choices. Unlike other services, Uber claimed that drivers all over the country could dearly alert customers that tipping is not included. Those drivers that expect to be tipped can make their wishes known. But the company is holding to its official no-tip-required line. “Once you arrive at your destination, your fare is automatically charged to your credit card on file－there's no need to tip.” Although drivers value the freedom to push a button rather than punch a clock like ordinary taxi drivers, lack of a clear policy leaves Uber drivers m a vulnerable (脆弱的) and awkward position: If they ask a customer for a tip or put up a sign, that customer could give the driver a low star-rating, and the driver could finally be removed from the app.

    But has the company done a good job working with customers? Some observers say that this new grey area for tipping will create awkwardness about whether they should tip or not. Providing an option to tip on an app sends a clear message to customers to reach into their pockets. According to Guinn's 2015 survey of roughly 500 people, merely 30% people would be more likely to leave a tip if they were presented with a “no tip” button.

    If the service is twice as expensive during a rain storm or public transport delay, the customer has the right not to tip, However, if the driver is extra helpful or avoids traffic to reach your destination in a more timely manner, you could give an extra tip, says Uber, who will leave tipping options in the hands of the consumer rather than the app.

    BKLYN House Hotel

    There are works by Brooklyn artists in this hotel. The 116 rooms are of great value and Manhattan is only 20 minutes away by taxi or subway. The immediate surroundings feel urban—the hotel is by a high-rise public housing project while the nearest commercial street is under elevated（高的）subway tracks—but Bushwick's best bars and cafes/restaurants are near-by.

    Doubles from $99, room only. Tel: 718 3884433

    Archer Hotel

    Visitors eager to stay in the heart of Manhattan should try one of the bargain-priced rooms at this hotel. Some start from as low as $179 a night (if prepaying in full). Rooms are small but tasteful, with nice touches such as exposed brick. Some have close-up views of the Empire State Building.

    Doubles from $199, room only. Tel: 212 7194100

    Pod 39 Hotel

    In an elegant brick building in Manhattan's Murray Hill, this excellent budget（预算）option opened following the success of its sister hotel, The Pod. The rooms are called pods given for their small size and may not suit everyone. But with prices among the most competitive in Manhattan, budgeters will be happy.

    Doubles from $95, room only. Tel: 212 8655700

    CitizenM New York Times Square

    This is the first US location for a Netherlands-based concept hotel chain—CitizenM. The hotel features self check-in at its 230 little but comfortable rooms via touch screen “Mood-Pads”. There's a rooftop bar, a 24-hour grab-and-go cafeteria and an area with public iMac workspaces. Although New Yorkers avoid nearby Times Square, all the lights, cameras and action can make it a fun tourist experience.

    Doubles from $170, room only. Tel: 212 319 7000

    There is little rain in desert. Because deserts are so dry, they have no “quilt” to help stop the soil from going away. As a result, they may get very hot during the day with the sun shining, but don't hold the heat overnight. Many deserts can quickly get cold once the sun goes down. Some deserts can reach temperatures of over 100 degrees F during the day and then drop below freezing (32 degrees F) during the night.

    The largest hot and dry desert in the world is the Sahara Desert in Northern Africa. The Sahara is a sandy desert with great sand hills. It covers over 3 million square miles of Africa. Other large deserts include the Arabian Desert in the Middle East, the Gobi Desert in Northern China and Mongolia, and Kalahari Desert in Africa.

    Animals that live in the desert are also used to needing little water. Many get all the water they need from the food they eat. Other animals keep water that they can use later. The camel stores up fat in its hump while other animals keep something they need in their tails.

    Only certain types of plants can live in the terrible environment of the desert. You won't see a lot of tall trees in the desert. Most plants have a way to keep water in their leaves, or trunks so they can live a long time without water.

    Now deserts cover around 20% of the world's land, but they are growing. This is called desertification and is caused by different reasons including human activities. The Sahara Desert is growing larger and larger each year. What should we do with it?

    Fashions have a lot of rules. Most of them, however, are just wrong. But there's one rule that goes beyond tradition and into the field of scientific study of the brain: Black garments are slimming. It all comes down to how your visual system processes the light. The below holes in each square are the same in size, yet the white hole looks bigger than the black hole.

    In the 1500s, Galileo Galilei noticed that some of the planets looked larger when viewed with the naked eye (肉眼) than they did when viewed through a telescope, making the white light of Venus (金星) appear eight to ten times larger than Jupiter (木星) in the night sky. He knew something strange must be going on with his vision to cause this illusion, but he wasn't sure what it was. Luckily, scientists never stopped wondering, and in 2014, they figured it out.

    Our visual system operates via two main channels: "on" neurons (神经元) that are sensitive to light things and "off" neurons that are sensitive to dark things. When it came to the dark "off" neurons, the researchers found that they responded predictably to dark shapes on a light background — the greater the contrast between the two, the more active these neurons were. But the light "on" neurons behaved unpredictably. Even with the same amount of contrast, light objects on a dark background caused a greater response in these neurons.

    This makes some sense, evolutionarily speaking. In the dark of night, you'd want to be able to take in every bit of light you can get, so a visual system that enlarges light objects on a dark background could be very useful. However, it's not that hard to see dark objects in the light of day. It has some effects in the colors of your clothes and in the appearance of the planets—the brighter appearance of Venus in the night sky makes it look bigger than the darker Jupiter.