Hearing is very important to all of us. We can 1beautiful music, nice songs of birds, the laughter of people or other different kinds of  2 in the world with our ears. 3 we must try to protect our ears. The following will tell you  4 protect ears.

    Listening to 5 usic a lot can be bad forears, especially when headphones are used. So 6 the volume(音) when you're wearing headphones or try not to wear headphones. You should give your ears a rest if you like wearing headphones.

    Before swimming, remember 7 earplugs （耳塞) into your ears or wear a swim hat to stop water from getting into your ears.

If you are going to a concert, wear earplugs to protect your ears 8 the terrible music! In fact, special earplugs can be made for you if you go to concerts a lot or if you are a musician yourself.

    See a doctor if your ears 9. Take some medicine if the doctor asks you to do so. Follow the advice above now and you won't be saying"what?"when you are getting 10.

    April 22 is Earth Day. Everyone on Earth should care about and protect the earth!

The earth has warmed by about 1°F (华氏度) over the past 100 years, but why and how? Well, scientists are not quite sure. Maybe the earth gets warmer and warmer on its own. But many scientists say that people are doing many things which make the earth warmer. First, greenhouse effect (温室效应) is a very important reason for the change of the earth. People give out too much energy into the air every year. It makes the earth warmer. Climate (气候) change is another important reason. Sometimes it becomes too hot and sometimes too cold. Sometimes there is too much rain and sometimes too little. The change of the climate makes the earth warmer. In turn, the warmth of the earth changes the climate, too.

When the earth becomes warmer, there may be more rain and a rise in sea level. It will affect the growth of plants, animals and people. On a Pacific island, 100 people have to move to higher ground because the sea is rising. These people can no longer live on the coast. Before that, two islands without people went underwater in 1999. Scientists say that the seas can rise by nearly one meter by 2100.

People can affect the earth's air, land and water. As for us, we can do many things to protect the earth. For example, we can use fridges less. We can tell more people about protecting the earth.

    Do you often drink bottled drinks? Of course 1  is so cool to get a cold one right out of the fridge, right? But all those plastic bottles use a lot of oil and  2 the environment. Americans buy 3 bottled water than any other nation in the world. In order to make all these bottles, 17 million barrels (桶) of oil  4up. That's enough oil to keep a million cars going for twelve months.

    Many people choose 5 the bottles away after having the bottled drinks. In fact, instead of going out with the trash, plastic bottles can be turned into carpeting for clothing. Remember this: Recycling one plastic bottle  6save enough energy to power a 60-watt light bulb for six hours.7 , for every six water bottles we use, only one is recycled. The rest are sent as garbage (垃圾). Or, even worse, they end up 8  trash on the land or in rivers and oceans.

    So why don't more people drink water from the kitchen? Some people drink bottled water 9 they think it is better for them, but that's not true. The chemicals in the bottles themselves may get into the water which can do harm to people.

    So next time when you have drinks or water, please  10 to use a glass at home or carry water in a steel bottle. And if you want to do something more, try to collect plastic bottles and send them for recycling.

    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."

    Suppose you find a bright yellow bike on a street corner in the city. You hop on(跨上)it and 1. But wait—isn't this stealing? No, it isn't. 2 shouts, "Stop! Thief!" That is 3 this free ride is just fine with the city.

    You 4 find hundreds of free yellow bikes in some US cities. The idea began in Portland, Oregon, in 1994. People saw a need for 5 transportation, and they wanted to help 6 pollution. So, to get citizens(市民) 7 their cars and onto pollution-free bikes, they 8 the Yellow Bike Project.

    The 9 bikes are painted bright yellow and placed throughout the city. People can hop on the yellow bike and ride to run errands(短程差事), to work 10 to school. Then, they leave the bike for the 11 rider. There have been times when bikes have been stolen, but most people 12 the rules, because they think it is not wise to 13 the bike that's already free.

    Portland's 14 was quickly loved by a lot of people. Within two years of its starts, similar programs were 15in cities in six other states.