You're thirsty and you get yourself a glass of water. Do you ever1how old that water really is? The glass of water that you're2may have fallen from the sky as rain only last week. However, water itself has been around pretty much as3as the earth has! In fact, 4oceans, seas and rivers cover 70％of the earth, there is a 5 supply(供给)of water, which keeps on moving round the earth. This is6of what's known as the water cycle. The sun heats up water and it turns into clouds, which are7from water vapor(水蒸气).When the clouds become8, the water falls back onto the earth as rain. Of course, clean water is absolutely essential for good health. The amount of safe drinking water has gone up around the world, but9one billion humans are still in great need10clean, drinkable water.

    We see many animals, like rabbits, bees, dogs, birds, sheep…，but do you know 1these animals say things? First，let's see a rabbit. When a rabbit sees 2dangerous(危险的)，it runs away at once. When it runs, its tail moves up and 3.When others see this, they run away,4.

    Many other animals use this kind of language(语言). When a bee has found some food, it goes back to 5home. It cannot tell6bees where the food is by speaking to them，but it does a little dance in the air. This may tell other bees 7the food is.

    Some animals say things by8sounds like a man does. For example，a dog barks when a stranger(陌生人)comes near. Some birds can make several 9sounds, each with its own meaning. In a word, every animal10its own language.

    It's very important that we all recycle. In nature, everything can be1again. For example, when an animal dies, it becomes 2animal's food. Nothing is wasted. But humans have created things like plastic bags 3can't be broken down by nature. Our rubbish kills animals and 4water and soil. 5we continue making too much rubbish, the problem will only get worse. If nature can't reuse the rubbish, we must recycle6.

    We should clean up the rubbish we've made because nature can't.

    Recycling is also the right thing to do for another reason. The earth is rich in natural materials like water and trees,7these materials are not endless. We use up our natural materials much8than the earth is able to reproduce them. For example, each year we cut9more that 6,000 square miles of forest. But it takes about 25 years 10a new tree to grow.

    Recycling can help us save the earth, so let's take action right now.

    We cannot stop earthquakes, but we can do things to make sure they do not destroy (破坏) whole cities. First, it is not a 1 idea to build houses along the lines where2of the earth's plates join together. Second, if you think there 3 be an earthquake, it is better to build houses on rock, not on 4. Third, you must make the houses as 5 as possible. Weak buildings will fall down in an earthquake, but strong ones may 6.

    Scientists are 7 that one day an even bigger earthquake will hit the part around S an Francisco. They call it “The Big One”. But people today are still building more 8. The population in and around San Francisco 9 is ten times more than it was in 1906. This means that 10 there is another earthquake, a great many houses and buildings will be destroyed.

    Australia is one of the largest countries in the world. It is 1 smaller than China. It is in the south of the earth. Australia is big, but its population is 2. The population of Australia is nearly as large as that of Shanghai.

    Enough laws have been 3 to fight against pollution. The cities in Australia have got little air or water pollution. The sky is blue and the water is 4. You can clearly see fish swimming in the rivers. Plants5very well.

    Last month we visited Perth, the biggest city 6 Western Australia, and went to a wild flowers' exhibition(展览 ). There we saw 7 large number of wild flowers we had never seen 8. We had a wonderful time. Perth is9 for its beautiful wild flowers. In spring, every year Perth has the wild flowers' exhibition.10visiting Perth, we 11 a day in the countryside. We sat down and had a rest near a path at the foot of a hill. It was quiet and we enjoyed ourselves. Suddenly we heard bells ringing at the top of the hill. What we saw made us 12all our things and run back to the car as quickly as we could. There were about three hundred sheep 13towards us down the path.

    Australia is well-known for its sheep and kangaroos. After a short drive from 14 town, you will find yourself in the 15of white sheep. Sheep, sheep, everywhere are sheep.