【推荐1】We have always been interested in the moon. 2, 000 years ago, people already knew it moves around the earth and where it would be in the sky at different times of the year. At that time, everything about the moon was learned by watching it carefully in the sky.

When scientists could use telescopes to study the moon more closely, their ideas began to change. They could see the moon was made of rocks. Most scientists thought moon rocks would be different from those on the earth. This was because they believed the moon had once been a planet that had been caught in the earth’s gravity (重力) millions of years earlier.

In 1969, moon rocks were finally brought to the earth and studied. Much to their surprise, scientists found that, except for water, the moon and the earth were made of the same things. Once again new ideas were needed for this new information.

After years of study, most scientists now think that the moon was once part of the earth. They believe very early in its history, maybe 4 billion years ago, something about the size of Mars hit the earth. This sent billions of rocks into space around our planet. These rocks slowly joined together and after many years became the moon.

In the future, though our ideas about the moon may change again, we will still be interested in it.

【推荐3】We all live on Earth and enjoy our life every day. Do you know all the interesting facts about the Earth?

The Earth is not round.

Do you think the Earth is round? Will the Earth is not completely round.

The Earth is really old.

Grandmas and grandpas are old, but the Earth is much older. Scientists think that the earth is about 4.5 to 5 billion (十亿) years old.

Much of the Earth is water.

About 70% of Earth is water, and only about 30% of Earth is land.

Earthquakes happen all the time.

Earthquakes (地震) take place all the time. But most of the time, they are very small and human beings cannot even feel them.

________.

There are many mountains on Earth. Mount Everest is the most famous one because its peak is five and one-half miles above sea level. It is the highest. There are more interesting facts about the Earth. Can you tell us some?

【推荐1】If you feel stressed at school, what can you do to make yourself happier? Some may eat their favorite food or listen to some music. Others may go for a walk or get some exercise. A new study found another great way to lower students’ stress—playing with dogs.

Scientists studied 105 students between the ages of eight and nine. 35 trained dogs and their trainers also took part in the test. The children were divided into 3 groups. The students in the first group spent 20 minutes with a dog and its trainer. They watched the trained dogs perform and even played with them. They did this twice a week for 4 weeks. The second group spent the same amount of time(时长) doing exercise to relax. The last group did neither of these things.

During this time, the scientists recorded the students’ cortisol levels(皮质醇水平). Cortisol is a stress hormone(激素).The more stressed you feel, the more cortisol you will have in your body. What did the scientists find? Both the second and third groups showed rises in cortisol levels. The first group, however, showed no big increase. And the children in this group had the lowest cortisol levels right after playing with the dogs.

According to the study, students enjoy playing with dogs, and it helps them become happier. The stress hormone falls over time this way, which is good for students’ health. But here comes the next question: Is 20 minutes of playtime with a dog the best amount of time? Scientists are going to keep working to find out the answer.

【推荐2】Most people agree that being honest is a good thing. But does Mother Nature agree? Animals can’t talk but can they lie in other ways? Animal experts may not call it lying, but they do agree that many animals behave dishonestly to fool other animals. Dishonesty (欺骗) often helps them live on.

Many kinds of birds are very successful at fooling other animals. A bird called the plover sometimes pretends (假装) to be hurt in order to protect its young. When an enemy gets close to its nest (巢), the plover pretends to have a broken wing. The enemy follows the “hurt” adult, leaving the baby birds safe.

Another kind of bird, the scrub jay, hide its food so it always has something to eat. Scrub jays also steal food. They watch where others hide their food and steal it. But clever scrub jays seem to know when others are watching them. So they get back later, get the food again, and hide it again somewhere else.

Chimpanzees can also be sneaky. After a fight, the losing chimpanzee will give its hand to the other. When the winning chimpanzee puts out its hand, too, the chimpanzees are friendly again. But an animal expert once saw a losing chimpanzee take the winner’s hand and start fighting again. When chimpanzees find food, it’s natural for them to cry out. Then other chimpanzees come running. But some clever chimpanzees learn to cry very softly when they find food. That way, other chimpanzees don’t hear them, and they don’t need to share the food.

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【推荐2】We’ve all seen the beautiful photos of colorful vegetables and freshly-baked cakes in books and magazines. When we see these pictures, we believe that if we follow the instructions that tell us how to cook them, we can make food that looks like that too. However, not many people realize the strange things that photographers (摄影师) use to change a simple plate of food into the ▲ dishes in the photos.

Food is one of the most difficult subjects for photographers. Hot food goes cold, cold food goes dry, and frozen food melts, making it useless. But don’t worry, because food photographers have the tools to deal with these problems. They don’t just visit photography shops. They also visit art shops, garages, and pharmacies (汽车修理厂和药店). As well as camera equipment, a photographer’s bag includes motor oil (机油) to help sauces (调味汁) look brighter, hairspray (发 胶) to stop cakes looking dry, and a spoonful of shoe polish to help meat look cooked.

There are a few rules about food that photographers have to follow. If a photo is going to become part of an advertisement (广告), rules say the food which people want to advertise must be the real thing. However, any other food in the photo doesn’t need to be real. Plastic “fruit” or glass “ice” in a drink next to the real dessert is acceptable, according to the rules. Of course, some photographers choose not to use non-food objects in their photos, even when the rules allow it, but that does make their job much more challenging.

Whether a food photographer believes in using tricks or not, one thing is true: food photography needs a lot of patience.

【推荐3】Online art classes have opened up a convenient space for people to get a start in the world of art. Tang Yingshan, a professor from The Open University of China in Beijing, started an online fine art education program. He believes that everyone can create a masterpiece painting.

Shan Lin, a woman from Guilin, has been learning fine art online for 17 months. She watches guide videos during lunch breaks and practices during her off-work hours. “There is a flexible(灵活的) learning timetable and the guide videos can be played repeatedly for us to have a better understanding,” Shan said. “The courses here don’t cost much and teachers from art schools are invited to give classes.”

Bai Li, who had worked for more than 20 years, became a student of Tang’s class. She used to think it difficult to learn oil painting. After learning basic drawing for one year, Bai planned to attend an advanced class. “Happiness is my biggest gain from learning oil painting,” said Bai, adding that painting gives her a chance to forget about her age and feel full of energy once again.

By January 2022, more than 36, 000 people from all walks of life had taken the online fine art education program. Although they have different jobs, they all find a way to express themselves in the world of art. Students at the beginner level are introduced into the world of art by copying world-famous paintings so that they can understand more about the artists’ styles and skills. “I think everybody is a talented painter. What we do is help them learn to express themselves like painters do,” said Xiao Fei, an art teacher of the program.

【推荐3】Trees are important in our daily lives. What are the parts of a tree?

Like many plants, a tree begins from a seed. A seed must have food, water and sunlight to grow.

All of the trees have roots. They go into the soil and have two important jobs to do: they make the tree stand, and they take in water and other things from the soil.

The trunk of a tree supports the branches of the tree and moves water and other things from the soil to the other parts of the tree.

Branches grow out from the trunk. They are the growing ends of the tree. They also move water and other things from the trunk to the leaves.

Leaves can catch sunlight. Using sunlight, the leaves produce food for the whole tree. Leaves use the water from the soil to make sugar to feed the tree. At the same time, trees release (释放) oxygen into the air. This is very important, because all the animals and humans need oxygen to live.