Hands play an important part in our daily life. But do you know which of your two hands you use more? Very few people use both hands equally well. Most of us are right-handed. Only about five people out of a hundred are left-handed. New-born babies can take hold of things with either of their hands, but in about two years they usually use their right hands. Scientists don't know why this happens.

Monkeys are our close relatives in the animal world. Scientists have found that monkeys like to use one of their hands more than the other, but it can be either hand. There are as many right-handed monkeys as left-handed ones. Next time you visit a zoo, watch the monkeys carefully, you will see that some of them will use their right hands and others will use their left hands. But most of the people use their right hands better and this makes life difficult for those left-handed people. We live in a right-handed world.

    The universe is really mystical(神秘的）.Scientists have done lots of study about it but there is still much they haven't discovered.

    Scientists think that there1life on the earth for hundreds of millions of years. However, we have not found life on any other planets2.

    There are eight planets going around the sun. The earth is one of them. There are humans, animals, and many other kinds of life on the earth. There is water and air, too. And compared to other planets, the earth is not too3or too cold. None of seven other planets has an environment like that of the earth.

    The sun and its planets are called the solar system, and our solar system is a small part of a4larger group of stars and planets, called the Galaxy or the Milky Way. There are5stars in the Galaxy, and our sun is only one of them.

    Scientists have also discovered many other galaxy in the universe. They are very far away and their light has to travel for many years to reach us. So 6is the universe? It is impossible to imagine.

    Scientists have sent spaceships to the planet Mars to7photos. They have even sent spaceships to travel outside 8 .However, no spaceship has traveled9to reach other stars in our Galaxy.

    When we see stars twinkling(闪耀）in the sky at night, we may think a lot:10so many stars in the universe, are we alone, or is there life out there in space? Have there been visitors to the earth from other planets? Why has no one communicated with us? We do not know the answer...

    As we know, life today has many problems. One of the biggest is 1, such as water pollution, air pollution, 2 pollution and so on. Water pollution makes our rivers and lakes 3. It kills fish and pollutes our drinking water. Air pollution is the most serious kind of pollution. 4 bad for living things in the world. Noise pollution 5 us talk louder and become angry 6.

    The Earth is 7 home and we must save it. We can't 8 rubbish here and there. We should go to work and school 9 bus or with our friends in the same car. Everybody 10 save the Earth.

    For the first time. scientist have made clones(克隆) of monkeys. A clone is a copy of a living thing. A team of Chinese 1used cloning to make two baby monkeys. Both are girls. They are named ZhongZhong and Huahua.

    Scientist have cloned other kinds of 2. They have cloned dogs and cats, they have also cloned pigs, cows and ponies. The 3animals to be cloned in the world was a sheep named Dolly. She 4in 1966.

    Scientist had never been able to clone primates (灵长类动物), Primates are a group of animals. They include monkeys. apes (猿) and people. Now, that has come true. Soon scientist may be able to clone 5 too. However, the Chinese scientist will not be cloning people, they will keep cloning monkeys6monkeys are more like people than other lab animals such as mice or rats. Lab animals can help to study diseases. Cloning monkeys is 7to the scientist for medical studies.

    However, there are still reasons that some scientists want to8people. For example, some parents might want to clone a child who has died. Yet the cloned Child would 9really be the same. They would look like the same, but would not be the same one. It might be hard for them to know that they were a clone of10else.

    Light travels at a very fast speed. It is about a million times1than the speed of sound. You can get some idea of this2by watching the start of a race. If you stand some distance away from the starter, you can see smoke from his gun before the sound gets to your 3.

    This great speed of light4some strange facts. Sunlight5about 8 minutes to get to us. If you look at the light of the moon tonight, 6 that the light rays(光线)leave the moon 1.3 seconds before they get to you. The nearest star is so7away that the light which you can see from it tonight started to8towards you several years ago. In some cases, the light from one of tonight's stars had started on its journey to you before you were born.

    So, to be exact, we can't say, "The stars are shining 9."We have to say instead, "The stars10pretty. They were shining several years ago, but their light has only just got to the Earth."