There are an extremely large number of ants worldwide. Each individual (个体的) ant hardly weigh anything, but put together they weigh roughly the same as all of mankind. They also live nearly everywhere, except on frozen mountain tops and around the poles. For animals their size, ants have been astonishingly successful, largely due to their wonderful social behavior.

    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 achieve this level of organization. Where we use sound and sight to communicate, ants depend primarily on pheromone (外激素), chemicals sent out by individuals and smelled or tasted by 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 its individual parts.

Model Railroading

    Would you like to know a fun way to learn about math? Well, you can do that with model railroading. Yes, it's true. You can learn about many school topics without using a school book. Besides that, there are many other benefits that model railroading brings us as well. In this article, we will discuss just a few of those benefits of model railroading.

Patience and problem solving skills

    When you build a model railroad, you have to plan your railroad out. You have to decide where the tracks (轨道) will go, where to put buildings, where to put streets and any other things you would like to add to your model railroad. Also, you have to think about any problems you may have with the design you choose. How will you make railroad crossings? How will you design hills, mountains, and rivers? Deciding on what to do with your model railroad takes a lot of thought and patience, but it is not as difficult as you may think.

Building skills

    With model railroading, you learn how to put together plastic models of buildings. Also, you can learn how to build a table for your design, or make scenery for the geography of your design. Your model railroad runs on electricity, so you learn about electronics as well. These are skills that not only help you build a model railroad; these skills will help you all throughout life.

Fun for family and friends

    Different from many video games, model railroading is a social hobby that lets you communicate with family and friends. This is because you have to communicate with family and friends as you build and run your model railroad. By spending time with the people in your life you love and care about, you learn to become closer and care more for each other. This is one of the best parts of model railroading as a hobby. Of course, the best part about model railroading is running the trains. Watching the trains run around the track and make all the sounds and do all the things that real trains do gives people hours of enjoyment. Also, there is great satisfaction in the fact that you, your family, and your friends built the model railroad.

    I hope you can learn to enjoy model railroading and experience all the benefits you just read about and many others. Happy railroading!

There's a song by the great Jamaican singer Bob Marley called So Much Trouble In The World. Marley understood that part of the reason why there are so many problems in the world is the lack of tolerance between people. The UN understands this too — that's why it made Nov 16th "International Day for Tolerance".

But first of all, what is tolerance? According to French philosopher Voltaire, tolerance "s the consequence of humanity. We are all formed of frailty (脆弱) and error; let us pardon each other's fool — that is the first law of nature."

    Very often, people don't realize that they're intolerant. This is because intolerance has a lot to do with ignorance. For example, the UN's campaign is in part about the treatment of females by males. But often, the behavior of men toward women is intolerant because men don't put themselves in the shoes of women.

    It's worth thinking a little about the words "tolerance" and "intolerance". Are they the best words to describe the evils of which we're speaking here? To agree to be "tolerant" of someone isn't necessarily a very respectful thing. When someone is tolerated, it implies that there's something wrong with them.

    Still, what Voltaire said stands: We humans are not perfect and this weakness is something that we all share. That's the reason we should be tolerant. It's a little like generosity. We can give things to another person, and we can also give our forgiveness.

    In 1800, only three percent of the world's population lived in cities. Only one city — Beijing — had a population of over a million. Most people lived in rural areas, and never saw a city in their lives. In 1900, just a hundred years later, roughly 150 million people lived in cities, and the world's ten largest cities all had populations exceeding one million. By 2000, the number of city dwellers exceeded three billion; and in 2008, the world's population crossed a tipping point — more than half of the people on Earth lived in cities. By 2050, that could increase to over two-thirds. Clearly, humans have become an urban species.

    In the 19th and early 20th centuries, many people viewed cities negatively — crowded, dirty environments full of disease and crime. They feared that as cities got bigger, living conditions would worsen. In recent decades, however, attitudes have changed. Many experts now think urbanization (城市化) is good news, offering solutions to the problems of Earth's growing population.

    Harvard economist Edward Glaeser, author of The Victory of the Cir, is one such person. Glaeser argues that cities are very productive because "the absence of space between people" reduces the cost of transporting goods, people, and ideas. While the flow of goods has always been important to cities, what is most important today is the flow of ideas. Successful cities enable people to learn from each other easily, and attract and reward smart people with higher wages.

    Another urbanization supporter is environmentalist Stewart Brand. Brand believes cities help the environment because they allow haft of the world's population to live on about four percent of the land. This leaves more space for open country, such as farmland. City dwellers also have less impact per person on the environment than people in the countryside. Their roads, sewers, and power lines need fewer resources to build and operate. City apartments require less energy to heat, cool, and light. Most importantly, people in cities drive less so they produce fewer greenhouse gases per person.

    So it's a mistake to see urbanization as evil; it's a natural part of development  The challenge is how to manage the growth.

Lots of sports idioms have found their way {#blank#}1{#/blank#} everyday language，{#blank#}2{#/blank#} make language more colourful and expressive.The English language is full of idioms which{#blank#}3{#/blank#} （think）to have come from football，such as "moving the goalposts"{#blank#}4{#/blank#} （mean）they unfairly change the rules or{#blank#}5{#/blank#} （require）of a process while "scoring an own goal"means that someone makes a bad mistake which {#blank#}6{#/blank#} （intention）harms their own interests.Baseball is another old and popular sport that has given the English language many different idioms. "Three strikes and you are out" is also an idiom that is often used to talk about situations {#blank#}7{#/blank#} you miss three chances.English also has a large number of idioms{#blank#}8{#/blank#} （relate）to boxing，which has been a popular sport for thousands of years.Sport is {#blank#}9{#/blank#}（challenge） and so is the study of the English language.Work hard，be careful not to score {#blank#}10{#/blank#} own goal，and you are sure to make it!

When you think about art, you might consider it to be permanent. After all, that picture you drew in kindergarten might still hang on your refrigerator years later. {#blank#}1{#/blank#} Think about a Broadway performance. When it's over, it's over. Sure, it might live in your memory. But the live show is a special event. It is limited to a certain time and place. 

Can you think of other forms of art that are temporary? If you're a fan of the beach, sandcastles might come to your mind. Have you ever spent hours building a beautiful sandcastle? {#blank#}2{#/blank#} You knew your work of art would be gone as soon as the tide came in. The sandy beach is a canvas where nature erases "paintings" daily. 

Most of the time, art made from sand can't last long. Still, many people love using sand to create their own unique vision of beauty. One of the most attractive types of sand art is sand animation. {#blank#}3{#/blank#} Artists who work in sand animation use sand to make a set of images that usually tell a story. They often start with a large amount of sand on a flat surface, such as a table. They then use their hands and fingers to draw in the sand. 

{#blank#}4{#/blank#} However, the wide variety of beautiful and highly-detailed sand artworks might surprise you. Many of these works or art are temporary. That's where the animation part comes in. 

Sand animation artists create a series of images that move to tell a story. They might also use music and special lighting to complete the effect. Sometimes they photograph or video their creation throughout the process. {#blank#}5{#/blank#}.

A. It is a type of live performance art. 

B. Not all works of art are permanent, though. 

C. Sand animation is beautiful but lasts only for the moment. 

D. Then, they turn it into a sand animation movie when it's finished. 

E. It might seem like using sand would limit the art you could make. 

F. If you have, you would probably be sad when it was time to leave the beach. 

G. Building a sand castle is a family-friendly activity perfect for large groups.