When an animal helps another animal, it usually gets something valuable (有价值的) in return. For a long time, many scientists thought that only people could act generously (慷慨地) just because it feels good.

However, a new study in Germany suggests that chimpanzees (an animal like a large monkey without a tail) also do good things for no real reason. And so do children who are as young as 18 months of age. Maybe it is because humans and chimpanzees share an ancestor about 6 million years ago.

People and chimpanzees appear to develop such features without any other training, says Warneken, a scientist in Germany.

Warneken and his partners worked on adult chimpanzees that live on an island in the African country of Uganda. They also worked with 18-month-old children in Germany. The researchers performed three experiments on the adult chimpanzees and two experiments on the kids. In the first animal experiment, a person tried to reach his arm into a cage to get a stick, but he couldn't reach it. A chimpanzee was in the cage, and it could reach the stick if it wanted to.

Thirty-six chimpanzees took part in this experiment one by one, and no chimpanzee saw what the other chimpanzees had done. Even though the animals hadn't met the person before, they usually took the stick and gave it to the person. What's more, they did this whether or not the person gave them bananas as a reward (奖励).

In a similar experiment, 36 children acted in a similar way. They helped the person reach the stick, whether or not they were given toys for their help.

Researchers did other experiments on chimpanzees and babies. No rewards were given in either experiment. And still, both the chimpanzees and children went out of their way to help.

Chinese dragons aren’t real animals, but they are very important in Chinese culture.

●Ruler (统治者) of water

Long long ago, Chinese people built temples (庙宇) for the “Dragon King”. When there was drought or flood (旱灾或水灾), people went to the temples to worship (敬奉) the “Dragon King”.

●A symbol of strength (实力)

For Chinese people, the dragon is a symbol of strength. If a person is excellent, they usually compare him to a dragon.

● A symbol of emperors

In China, emperors usually used the dragon as a symbol of their power (权力). They called their beds “Dragon Beds”

●Chinese dragons VS Western dragons

In Chinese culture, dragons are kind and friendly. However, in Western culture, dragons are bad. So dragons are always killed by brave people in Western stories.

For thousands of years, dogs have held a special place in people’s hearts. They are known as “ man’s best friend” . This is because they can be so brave, lovely, and loyal（忠诚）. Dogs are used to living in groups and following the leader. Now humans are their leaders. Dogs depend on people for food— mostly meat— and perform services in return.

Long long ago, dogs worked for people. They ran after wild animals, caught them on land and water, and protected houses. They are used to send messages, look after sheep, and even save people in snow. They help police find out what they want. Fast-runningdogs are used in races.

Dogs have many abilities that make them useful. Sharp teeth are only one of these. Most dogs can smell something human can’t smell and hear higher notes than any person. And although dogs don’t see many colors, they are very good at noticing movements.

Dogs come in many shapes, sizes, and characters. A big Irish dog stands about 32 inches tall. However,some dogs stand about only 5 inches tall. Dogs that can guard homes are intelligent. Police dogs are usually quite brave. But many different kinds of dogs now make playful family pets.

Dogs have been kept to work for human for a long history. When Pompeii— the ancient Italian city that was buried about 1900 years ago— was dug out, a dog was found lying across a child. It was trying to protect the child.