As we know, we all need a healthy environment. I wonder  1  we can work to reduce carbon dioxide(二氧化碳)around us. Well, here 2  some ways to follow.

    ▲Only turn the water heater  3 when necessary, and the temperature controls to avoid overheating. Put a lid on a pan when boiling water.

    ▲When using the washing machine, be sure there's a full load and turn the temperature down  4  it's not really dirty.

    ▲Save energy by using efficient(节能的) light bulbs. They use about 5  the energy of normal bulbs and last 10 times as long.

    ▲Each week, choose one day when you don't eat meat. Meat uses up lots of energy because it  6 a long time to produce.

    ▲Food production eats up lots of energy. When you buy food, go local rather than imported(进口的), and get fresh vegetables  7 frozen(冷冻的).

    ▲Take showers rather than baths and reduce your shower time by two minutes. This  8 water and give you an extra two minutes in bed.

    ▲ Look for something reusable and recyclable, and remember  9  your reusable shopping bags!

We can do more things to recycle  10 we can reduce carbon dioxide in the air and we all have a strong and healthy body.

    The world's population is larger and larger. There will 1 much more people next century. The earth will be more crowded and there must be a little room 2 each person. Perhaps there will be 3 room only on the earth a few centuries later. That will be serious to humans.

    So human are 4 of a good way to solve the problems.

    The moon is the 5 that is nearest to us. Maybe man will 6 on it some day. According to the scientists, studying, we know that there is no air, no plants, no water and no life there. So scientists are doing experiments 7 many ways. They 8 solve a lot of problems 9 humans can live on the moon. I'm sure the dream must 10 in the future. Maybe it is in the next century.

    Natural resources are things that we use that come from Earth.  Out natural resources are limited(有限的). This means that they will not1 forever.

    Some are renewable, like when you plant a new tree when you2one down. Others are not renewable, like when you dig coal out of the 3.Once it is used, it is gone. People realize the4that Earth's natural resources are limited, and can do things to help save those resources.5you try to save a natural resource, you try to use less of it, so it does not run out so 6 One way that people save fuel, like gasoline, is by riding a bicycle or walking when the 7is short instead of driving everywhere. Water is a very important natural resource because we all need it to stay8. We can keep water9making sure that our pipes and taps do not leak(漏). We can also make 10 choices to save water, like only using the dishwasher or washing machine when they are full.

    Everyone can make contributions to protecting natural resources.

    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 there 1 life on the earth for many many years. However, we haven't found life on any other planets 2

    There are eight planets going around the sun. The earth is one of them. There are humans, animals, plants and many other kinds of life on the earth. There is water and air, too. And compared to the other planets, the earth is not too 3 or too cold. None of seven other planets has av. 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 a 4 larger group of stars and planets, called the Galaxy or the Milky Way. There are 5 stars in the Galaxy, and our sun is only one of them.

    Scientists have also discovered many other galaxies in the universe. Their light has to travel for many years to reach us. So 6 is the universe? It is impossible to imagine.

    Scientists have sent spaceship to the planet Mars 7photos. They have even sent spaceships to travel outside 8 . However, no spaceship has traveled 9 to reach other stars in our Galaxy.

    When we see stars twinkling(闪耀) in the sky at night, we may think a lot:10 so many stars in the universe, is there life out there in space? If there is life on other planets, what life will be like there? What transports do they use to travel? Why don't they visit us? We do not know the answers…