When man began to search the skies, he saw a lot of things. In the universe, the earth seemed to be just a small bit of dust. It is only a small planet, and travels around the sun. The sun together with its planets, travels in the Milky Way（银河）, our galaxy（星系）. The Milky way has about thirty billion stars like our sun, and is one of about a hundred million galaxies in the universe. Because the space is so great, it is difficult to work out how far away a star is. Instead of kilometers, we have light years. A light year means the distance light travels in one year. Our nearest neighbour galaxy is more than 9,000,000 light years away from the earth.

    Natural resources are things that we use that come from the earth. Our natural resources are limited(有限的). This means that they will not1forever. Some are renewable, like when you plant a new tree when you cut one down. Others are not renewable, like when you dig coal(煤) out of the 2Once it is used, it is gone.

    People realize the 3 that the earth's natural resources are limited, and can do things to help conserve(节约) those resources.4you try to conserve a natural resource, you try to use less of it, so it does not get used up so5One way that people conserve fuel, like gasoline, is by riding a bicycle or walking when the6is short instead of driving everywhere.

    Water is a very important natural resource because we all need it to stay 7We can conserve water8making sure that our pipes and taps do not leak(泄露). We can also make wise choices to conserve water, like only using the dishwasher or washing machine when they are full. Everyone can make contributions to protecting natural resources.

    John comes from England. When he comes to China, his friends tell him something about the traffic 1 in China. People drive on the2 in England, but in China, people should drive on the right. Before you cross street, you must look 3 ways look left, look right and look left again. 4 remember the traffic moves on the right in China, or some cars and some buses may5 you.

    In the morning and the evening. when people go to work and 6 back from work, the streets are very busy(累忙的). 7  it is the most dangerous(危险的)time. When you want to 8 the road, you must 9 for the green "walk" sign.

    In China, you can always  10  the policeman for help when you lose your way.

    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.

     Xinhua News Agency reported 3,000 yellow school buses started their service in Chongqing1the end of 2011. These school buses are like the ones in the US as we usually see on TV and in 2 .

    The school buses are bright yellow in colour. They are 3than the army's cars. They are from the US. The yellow school bus has a big 4.This keeps the students safe when other cars crash into the school bus. The bus also has some   5devices(设备), such as warning lights and a stop signal arm.

    In China, school buses became popular in the past few years. On the bus, except(除了) the bus driver, there is always a 6whose duty is to watch the students. Children usually rest on the bus. Some of them also recite texts. School buses in China are not 7.The fee is different from school to school.