Do you know why different animals or pests have their special colours? Colours in them seem to be used mainly to protect themselves. Some birds love eating locusts (蝗虫), but birds cannot easily catch them, why? It is because locusts change their colours with the change of the colours of crops. When crops are green, locusts look green. But as the harvest (收获) time comes, locusts change to the same brown colour as crops have. Some other pests with different colours from plants are easily found and eaten by others. So they have to hide themselves for living and appear only at night.

    If you study animals' life, you'll find the main use of colour is to protect themselves. Bears, lions and other animals move quietly through the forests and they cannot be easily seen by hunters. This is because they have the colours much like the trees.

    Have you ever noticed an even stranger act? A kind of fish in the sea can send out a kind of very black liquid (液体) when it faces danger. While the liquid spreads, its enemies cannot find it. And it immediately swims away. So it has lived up to now though it is not strong at all.

Green is an important color in nature. It is the color of grass and the leaves on trees. It is the color of most growing plants, too.

Sometimes, the word green means young, fresh and growing. Sometimes, it describes something that is not yet finished or plants that are not ripe.

For example, a greenhorn is someone who has no experience, who is new to a situation. In the fifteenth century, a greenhorn was a young cow or ox whose horns had not yet developed. A century or so later, a greenhorn was a soldier who had not yet had any experience in war (战争) .By the eighteenth century, a greenhorn had the meaning it has today——a person who is new in a job.

About one hundred years ago, greenhorn was a popular expression in the American west Old—timers used it to describe a man who had just arrived from one of the big cities in the east. The greenhorn didn't have the skills that he would need to live in the hard, rough country.

Someone who has the ability to grow plants well is said to have a green thumb. The expression comes from the early nineteen hundred.

A person with a green thumb seems to have a magic touch that makes plants grow quickly and well. You might say that the woman next door has a green thumb if her garden continues to grow long after your plants have died.

The Green Revolution (革命) is the name which was given some years ago to the development of new kinds of rice and other grains. The new plants produced much larger crops. The Green Revolution was the result of hard work by agricultural (农业的) scientists who had green thumbs.

    When people think of tigers, words like" strong" and " dangerous" come into their mind. But now, the big animal is calling for our help. There were once eight kinds of tigers in the world, but three died out during last century. In the past 70 years, the number of Siberian tigers has gone from as many as 300 to somewhere between 18 and 22.

   World Wildlife Fund started a programme. It is about to put an end to tiger poaching(非法狩猎) and save wild tigers. China, together with 12 other countries, has joined in. The aim is to double the number of wild tigers in the next ten years.

According to the research by Chinese officers and WWF, the Siberian tiger is already one of the planet's most endangered animals. "If the government doesn't do anything, it's quite possible that there will be no more Siberian tigers in China in 10 to 20 years." said Zhu Chunquan, director at WWF Beijing office.

    Wild animals such as deer and wild bears are tigers' main food. The poaching of these animals is the greatest danger to tigers. Another one is the trap(陷阱). "Volunteers from WWF remove traps every year, but we cannot clear all the traps ourselves," Zhu said. The most important thing people can do is to save the animals tigers eat." To protect the tigers, we need to call on more people to stop hunting wild animals."

    Do you know Singles Day (November 11) in China? Many people, even your parents, go to bed late that night. They were shopping online to get big savings (省钱). Well, the US has something like it called Black Friday.

Black Friday is the Friday after Thanksgiving. It is on November 27 this year. It is one of the biggest shopping days in the US. People want to start shopping for Christmas gifts, so they go shopping on this day to save money.

It's called Black Friday because shops used to record (记录) sales with black ink (墨水). So when there was a lot of black ink on a page, the shop sold a lot.

On Black Friday, people go shopping at actual stores (实体店). It is different from Singles Day. People stand in line (排队) for hours. Sometimes they fight over things because there are only a few left. TVs, computers and video game systems are some of people's favourite things to buy.

Clark and Dale were staying in the same room in a hospital. Clark was so sick that he could not even move his body._He had to spend all his time lying on his back. Dale could sit up in his bed for an hour each afternoon. His bed was next to the room's only window. 

Over time, Clark and Dale became good friends. Every afternoon, Dale would look out of the room's only window, describing the scenery outside for his friend. He told Clark about the flowers in a park outside the window, the people walking by, the green trees beside roads—anything that might interest a man. 

One morning, when a nurse came to check on the two men, she found that Dale had died in his sleep. As soon as the room seemed tidy again, Clark asked if he could move to the bed next to the window so that he could look out of the window himself. The nurse agreed. Slowly, he could take his first look at the world outside. To his surprise, he could see nothing but a blank wall of another building. 

The nurse explained that Dale had been blind. He had never seen anything outside the window at all—but he described beautiful scenes to help his friend feel better. 

It's 8：00 am. A new term(学期)begins. This is the first class. 

Betty's new teacher comes into the classroom. She is a nice girl. "Good morning, boys and girls. Welcome to Class 3, Grade 7. I'm your English teacher—Helen Miller. You can call me Ms Miller or Helen. I'm from London and my phone number is 8336 001. I hope you like me. " 

"I like you, Helen，"one girl says. "My name's Kate King. I'm from Oxford. My phone number is 8975 002. " Then Kate gives a red flower to Ms Miller. 

"Helen, I love you，"one boy says. "I'm Dave Black from Cambridge. My phone number is 8790 041. "And Dave gives a red flower to Ms Miller, too. 

After that, two girls stand up and say, "We like you, too, Ms Miller. " Helen is surprised (惊讶的) to see them. They look the same. "We're twins from Liverpool，"one girl says. "I'm Lucy Brown and she is Lily Brown. Our phone number is 8790 032. " Then Ms Miller gets two red flowers again…