Many people know that rubbish is a big problem on planet Earth. What many people don't know is that junk (垃圾) has become a problem in outer space too.

    According to BBC News, there are more than 22, 000 pieces of space junk floating around the earth. Andtheseare just the things that we can see from the surface of the earth by telescopes (望远镜). There are also millions of smaller pieces of junk that we can't see.

    Objects, like bits of old space rockets or satellites, move around the planet at very high speeds, so fast that even a very small piece can break important satellites or become dangerous to astronauts. If the tiniest piece of junk crashed into a spaceship, it could damage the vehicle.

    To make things worse, when two objects in space crash, they break into many smaller pieces. For example, when a U. S. satellite hit an old Russian rocket in 2009, it broke into more than 2,000 pieces, increasing the amount of space junk.

    To reduce additional space junk, countries have agreed that all new space tools can only stay in space for 25 years at most. Each tool must be built to fall safely into the earth's atmosphere after that time. In the upper parts of the atmosphere, it will burn up.

    Many scientists are also suggesting different ways to clean up space junk. In England scientists are testing a metal net that can be fired into space junk. The net catches the junk and then pulls it into the earth's atmosphere to burn up. The Germans are building robots that can collect pieces of space junk and bring them back to Earth to be safely destroyed.

    "The problem is becoming more challenging because we're sending more objects into space to help people use their mobile phones and computers," says Marco Castronuovo, an Italian space researcher.

    "The time to act is now. The longer we leave the problem, the bigger it will become," he says.

Chopsticks are an important tool to have meals in China.

When were chopsticks invented?

{#blank#}1{#/blank#} They were invented before Shang Dynasty. The earliest   chopsticks were made of bronze (青铜). They were 26 centimetres long and 1.1 to 1.3 centimetres wide. People used them to pick up food at that time.

{#blank#}2{#/blank#}

Most people believe that Chinese invented chopsticks. There are many stories about the inventor of chopsticks. Someone says that Jiang Ziya, a wise man, created chopsticks. Actually, no one knows for sure. We can only say that the inventor was a clever ancient Chinese.

What shape are chopsticks?

Chopsticks have the shape of being square above and circle below. Chinese believe that the Earth is square and the sky is circle. {#blank#}3{#/blank#}

How are chopsticks used?

Many people think it's difficult to use chopsticks. {#blank#}4{#/blank#} Hold them between the thumb and other fingers. The key is to hold one piece tight and move the other to control movement and force. Remember, practice makes perfect.

Chopsticks are also one important part of Chinese culture. In China, it is polite to pick up food for the old. {#blank#}5{#/blank#} And never make your chopsticks stand straight in a rice bowl. Don't use chopsticks to hit the side of your bowl, either.

Every year thousands of students leave school for a few weeks or months and enjoy an unusual type of educational program. What they learn during this time does not come from books. They learn new skills by living in a different country and doing unusual jobs. There are several programs that help students to gain (获得) the experience they are looking for.

One interesting program is saving elephants in Thailand. Most people think of elephants as animals in zoos or circuses. However, many elephants are no longer kept in captivity (囚禁). Now, hundreds of them are homeless. These gentle animals are often found on the streets because they do not have owners to care for them. Although they may look well, they are often in poor health and don't have enough food to eat.

One center in Thailand cares for these elephants. It provides a safe and natural living space for them. When they are at the center, they stay in a building but are free to walk around. Students come from all over the world to help there. The students work with the elephant keepers and help then a train elephants. These keepers teach the students how to care for the elephants. In the morning, they go to the forest together and lead the elephants to the center. They clean them and give them food. In the afternoon, they take the animals back into the forest for the night. Helping at the center is interesting and the young people learn a lot.

What season is it in October? If you ask people from UK, they will tell you it's "autumn". But if you go to US, you will find that people use "autumn" or "fall". 

According to Dictionary. com, both words have been around for a long time. but neither of them was first to describe this season. During this season. crops would become ripe（成熟）and farmers would have a big harvest. So in Old English, this season was simply called "harvest". 

Then, in the 1600s, more people left their farms and moved to cities. With fewer people farming the word "harvest" became less useful. English speakers needed a different name for the season. They knew leaves fell from trees during the season, so people started calling it "the fall of the leaf", or "fall" for short. 

But at the end of the 1600s, autumn, from the French word "autompne" and the Latin "autumnus", came to English. "Fall" as the word for this season disappeared slowly. 

At the same time, people in UK were making their first trip to North America. They brought the words "fall" and "autumn" with them. That's why today Americans have two names for one season. 

Making new friends can be difficult, especially if you are a child in a new neighborhood. It may seem like everyone else has a friend to sit with or to talk to. Don't worry:if you're a nice person, you can make friends,too. 

Step 1. Decide what kind of people you want to play with. Choose (选择) wisely, because you'll probably become like them. Pick children that are nice to other people. 

Step 2. Smile and say something nice to the person you want to be your friend. If you like a person's shoes or think a girl is good at basketball, just say so. Everyone likes compliments. 

Step 3. Join clubs and teams. If you like sports, try out for some. Put yourself in situations where you are around many children that enjoy the same activities as you. It's easier to develop (发展) friendships when you have the same hobbies. 

Step 4. Ask questions whenever it's appropriate(适当的). People love to talk about themselves. Be careful not to ask too personal questions or ask someone too many questions. But asking one or two questions shows you're interested in him or her.