In colonies (群体) that range in size from a few hundred to tens of millions, they organize their lives with a clear division of labor. Even more amazing is how they achievethis level of organization. Where we use sound and sight to communicate, ants dependprimarily on pheromone (外激素), chemicals sent out by individuals and smelled or tastedby fellow members of their colony. When an ant finds food, it produces a pheromone that will lead others straight to where the food is. When an individual ant comes under attack or is dying, it sends out an alarm pheromone to warn the colony to prepare for a conflict as a defense unit.

         In fact, when it comes to the art of war, ants have no equal. They are completely fearless and will readily take on a creature much larger than themselves, attacking in large groups and overcoming their target. Such is their devotion to the common good of the colony that not only soldier ants but also worker ants will sacrifice their lives to help defeat an enemy.

         Behaving in this selfless and devoted manner, these little creatures have survived on Earth, for more than 140 million years, far longer than dinosaurs. Because they think as one, they have a collective (集体的) intelligence greater than you would expect from itsindividual parts.

    By now, we are all aware that social media has had a powerful influence on our culture, in business, on the world at large. Social media websites revolutionized the way people communicate and socialize on the Web. However, besides seeing your friends' new baby on Facebook, or reading about Justin Bieber's latest conflict with the law on Twitter, what are some of the real influences?

    Social networks offer the opportunity for people to reconnect with their old friends and acquaintances, make new friends, share ideas and pictures, and many other activities. Users can keep pace with the latest global and local developments, and take part in campaigns and activities of their choice. Professionals use social media sites like Linkedln to improve their career and business development. Students can work together with their peers to improve their academic and communication skills.

    Unfortunately, there are a few downsides too to social networking. If you are not careful, immoral people can target you for cyber bullying(网络欺凌) and disturbance on social sites. School children, young girls, and women can fall victim to online attacks which can create tension and suffering. If you are a victim of cyber bullying, do not take it lying down, but try to take appropriate legal action against the attacker.

    Many companies have blocked social networks as addicted employees can distract (分心)themselves on such sites, instead of focusing on work. In fact, studies show that British companies have lost billions of dollars per year in productivity because of social media addiction among employees.

    Also, what you carelessly post on the Net can come back to trouble you. Leaking personal information on social sites can make users easily harmed to crimes like identity theft, stalking(尾随犯罪), etc. Many companies perform a background check on the Web before hiring an employee.  If a potential employee has posted something embarrassing on social media, it can greatly affect their chances of getting the job. The same holds true for our relationships too, as our loved ones and friends may get to know if we post something undesirable on social networks.

    Social media has its advantages and drawbacks as each coin has two sides. It is up to each user to use social sites wisely to improve their professional and social life, and exercise caution to ensure they do not fall victim to online dangers.

                                                                                              The National Gallery

    Description:

    The National Gallery is the British national art museum built on the north side of Trafalgar Square in London. It houses a diverse collection of more than 2,300 examples of European art ranging from 13^th-century religious paintings to more modern ones by Renoir and Van Gogh. The older collections of the gallery are reached through the main entrance while the more modern works in the East Wing are most easily reached from Trafalgar Square by a ground floor entrance.

    Layout:

    The modern Sainsbury Wing on the western side of the building houses 13th- to 15th-century paintings, and artists include Duccio, Uccello, Van Eyck, Lippi, Mantegna, Botticelli and Memling.

    The main West Wing houses 16th-century paintings, and artists include Leonardo da Vinci, Cranach, Michelangelo, Raphael, Bruegel, Bronzino, Titan and Veronese.

    The North Wing houses 17th-century paintings, and artists include Caravaggio, Rubens, Poussin, Van Dyck, Velazquez, Claude and Vermeer.

    The East Wing houses 18th- to early 20th-century paintings, and artists include Canaletto, Goya, Turner, Constable, Renoir and Van Gogh.

    Opening Hours:

    The Gallery is open every day from 10am to 6pm (Fridays 10am to 9pm) and is free, but charges apply to some special exhibitions.

    Getting There:

    Nearest underground stations: Charing Cross (2-minute walk), Leicester Square (3-minute walk), Embankment (7-minute walk), and Piccadilly Circus (8-minute walk).

    If you were an exchanged student in New York City, one day your math teacher gave you following questions as your homework, please write down your answers.

    Ⅰ.A company sold a product for α dollars in 1990. The price of the product would increase by 2.5% every year.

    Ⅱ.A man needs to make 3 curtains. The cloth which is used to make curtains sells for $8.00 per meter and can be purchased only by the full（完整的） meter. The length of cloth required for each curtain is 1.6 meters.

    Ⅲ.A pet store sells only dogs and cats. In March, the store sold twice as many dogs as cats. In April, the store sold twice the number of dogs that it sold in March, and three times the number of cats that it sold in March.

Both humans and animals have enemies. 11 is easy for us to know the difference between our friends and our enemies. But can other animals do the same? Elephants can! They can use their sense of vision and smell to tell the difference between people who mean a threat and those who do not. In Kenya, researchers find that elephants react differently to clothing worn by men of the Maasai and Kamba ethnic groups. Young Maasai men hunt animals and thus mean a threat to elephants; Kamba men are mainly farmers and are not a danger to elephants.

In an experiment conducted by animal scientists, elephants were first presented with clean clothing or clothing that had been worn for five days by either a Maasai or a Kamba man. When the elephants noticed the smell of clothing worn by a Maasai man, they moved away from the smell faster and took longer to relax than when they noticed the smells of either clean clothing or clothing worn by a Kamba man.

Clothing color also plays a role. In the same study, when the elephants saw red clothing not worn before, they reacted angrily, as red is typically worn by Maasai men. Rather than running away as they did with the smell, the elephants acted angrily toward the red clothing.

The researchers believe that the elephants' emotional reactions arc due to their different senses of smell and sight. Smelling a possible danger means that a threat is nearby and the best thing to do is run away and hide. Seeing a potential threat without its smell means that risk is low. Therefore, instead of showing fear and running away, the elephants express their anger and become aggressive.

    A man went into a restaurant and sat down at a table. He ordered the most expensive dishes. The waiter served the meal. He ate it with great joy. Then a small boy came in and sat at his table.

    The waiter came up and said to the man, "What would your little boy like, sir?"

    "Oh, just an ice cream," the man told him. Then he stood up and said to the waiter, "I'm just going out to buy a newspaper."

    He left the restaurant. The waiter gave the boy an ice cream. The boy took it and then stood up and walked to the door. The waiter ran towards him.

    "Excuse me," he said, "But your father hasn't come back and he hasn't paid for his meal or for your ice cream."

    "He's not my father," the boy said. "I don't know him at all."

    The waiter was puzzled. "What do you mean?" he asked.

    "The man came up to me in the street," the boy said, "He asked me if I liked an ice cream. I told him I did. Then he told me to come into the restaurant at 2 o'clock and sat down at his table. He said he'd give me one."