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    The Earth is our home; we must take care of it. This means keeping the land, air and water clean. Pollution is a dirty word. To pollute means to make things unfit or unclean to use. Pollution comes in many ways. We see it, smell it, taste it and drink it. Pollution is beginning to threaten (威胁) our health, our happiness and our life. Man has been polluting the earth from the time he first made fire, washed his clothes in the river and threw his waste on the ground. When land was used up or water became dirty, men moved on to another place. At first, the problem was not so serious because there was plenty of clean air, land and water. There weren't so many people then and their wants were fewer. All the dirty things could be absorbed (吸收) by nature and soon covered over. But this is no longer true. The increase of population and the development of industry(工业)have changed that. Man is slowly poisoning (毒害) his environment. Through the use of poison, man has polluted the land, killing the animals. By putting dirty water and chemicals into rivers and lakes we have polluted our drinking water, killing the fish.

    Our increasing population is part of the problem. More people, more waste.

    Where is this all to end? Are we turning the world into a big rubbish dump (堆存处), or is there any hope that we can get rid of (摆脱, 除去) the pollution? Luckily, millions of people have been warned of the danger of pollution. Large numbers of people are now working hard to bring pollution under control.

    Do you believe that only boys do well in science? Does it seem that girls have better language skills than boys? In your opinion, are boys better at building things? If your answer to each of those questions is" Yes", you are right, according to an article in Current Science. There are exceptions(例外),but here are the facts.

    Usually, boys score higher in tests about math, while girls do better in tests about words, spelling and memory. But these differences may not always be true. In the future, a person's abilities may not be decided by sex. As one scientist says, "Nothing is impossible for a person to be or do."

    A recent study by Jerome Kagan, a scientist at Harvard University is studying the watching ability of children who are 10 months old. Baby boys and baby girls are watching "show" while seated on their mothers' laps. In Act One of the show, an orange-colored ball is lifted from a blue box and moved slowly. Then it is returned to the box. This is repeated six times. Act Six is almost the same, except that the orange ball is smaller. Baby boys do not seem to notice the difference in the size of the ball, but girls immediately become excited and begin to make noises that sound like language.

    It's also known that baby girls usually talk at an earlier age than baby boys do. Scientists believe that the left side of the brain develops faster in girls than in boys. As a result, by the time they start to go to school, little girls have an advantage that boys don't have, but what have the boys been doing in the years before starting school? They have been developing something called aggression. An aggressive person feels strong and independent. He is often the first one to start a fight. It is said that aggression is caused by hormones(荷尔蒙). Scientists believe that hormones are not the only cause. They say aggression in boys is also caused by mothers.

Imagine a perfect day: the weather is good and everything seems fine. When, suddenly, your mobile phone loses its signal, the television has no programmes, and you can't get online with your computer.

What has happened? These are just the types of problems a solar storm（太阳风暴）might cause. You may not think of storms as putting our society in danger. But today, a solar storm is as serious as other bad events, such as earthquakes.

A solar storm is caused by solar flares（太阳耀斑）: large explosions（爆炸）near the Sun that can give off lots of energy. The strong energy can stop the satellite systems（卫星系统）that control our computers, telecom networks and so on. These storms can even cause the power to go out for weeks or months.

Scientists have recorded some of the strongest sun flares in years. One happened around Valentine's Day, 2011. It caused radio and satellite signals to go down in some northern cities in China.

"Solar flare activity is going to be much worse than what we've seen in the past. We're not talking about a few cities losing power, it could behalf of the country, maybe more," Solar Storm Warning.com, a US website about space weather, warned.

Scientists say that little can be done to predict such a storm. Governments around the world are trying to work together before the next storm, although they are not sure when that may happen.

Have you ever seen or used a saw, or" ju" in Chinese? Do you know who invented it?

The inventor was Lu Ban. He was born in the state of Lu in ancient China more than2,500 years ago. That is where Qufu lies in the east of Jining.

Lu Ban was the greatest carpenter(木匠) in his time. Once the king ordered him and his team to build a palace in a very short time. They would be punished if they missed the deadline(最后期限). They had only axes, or fuzi in Chinese, to cut the trees and prepare the wood for the palace, so work was very slow.

One day Lu Ban rushed up the hill to see how things were going. Suddenly the sharp teeth of a leaf cut his hand. Then a bright idea came into his head. Soon he made a tool with teeth along the side of a long iron bar(条状物). With this tool, work became much faster, and they completed the work before the deadline.

That is how the saw was invented.

Lu Ban invented many other useful tools for carpenters and interesting toys for children. The Wooden Bird, for example, could stay in the air for three days. That's why he is regarded as the God of Carpentry.

When we talk about table tennis, China may be the first country that comes to your mind. It is known as the {#blank#}1{#/blank#}(nation) ball game of China. But do you know {#blank#}2{#/blank#} this beautiful game was first created?

In the 1870s, people in England loved {#blank#}3{#/blank#} (play) lawn(草地) tennis. But in winter, the weather was too cold. People {#blank#}4{#/blank#} wanted to enjoy the sport indoor started a new kind of tennis. They played it on their dining tables. That's why the sport is called" table tennis".

Later, more table tennis lovers {#blank#}5{#/blank#}(bring) table tennis to other countries. In 1904, it {#blank#}6{#/blank#} (introduce) to China. Chinese people quickly fell in love with the game. They would play it very {#blank#}7{#/blank#} (active)— almost everywhere.

Thanks to an Englishman, Ivor Montagu, China was able to be a member of ITTF. In1959, China won the World Championship {#blank#}8{#/blank#} the first time. In 1988, table tennis became {#blank#}9{#/blank#} Olympic sport. The Chinese table tennis team did well in Tokyo 2020. They won four gold medals and three {#blank#}10{#/blank#} (silver)! It was really a great success.