Americans love cars. They go everywhere in them. 85% of people in the US go to and form work by car. And most adults have driving licenses. Why does this car culture exist?

How it started

America's love of cars started after the war when soldiers returned home from World War Π to rebuild their lives. They borrowed money from the government to buy houses and cars which became the symbols of status（地位）. The more money they had, the bigger their cars were.

Making of roads

During the war, President Eisenhower noticed what good roads Germany had. He decided to build new four-lane（四车道）roads in America. He said is something happened suddenly, the two-lane roads wouldn't be able to carry all the cars that would suddenly leave the cities. Car and oil companies liked his idea and building started.

Car lovers

Not just teenagers are crazy about cars. Some Americans love their cars so much that they paint their cars beautifully. These are called Art Cars. Every April there is an activity in Houston, Texas, where they show their cars.

Pollution

Cars have polluted the environment. American President Bush refused a worldwide law that is against pollution. Many countries were angry about it. Bush said he had to think of the American economy（经济）and all the American people that make money from cars. Factories say they want to make cars that pollute less. But others say making cars that pollute less will never be as good as having fewer cars.

The Smallest Life Around Us

    Tiny plants and animals live all around us．We cannot see them because they are so small，but they are everywhere. They live in the soil，in the air，and in rivers and oceans．They grow on mountains and in caves．Some live in the ice at the north and south poles; some live where it is very hot．They are found throughout cities and in the country. They grow on other plants and animals．Some are even living on you，on your skin，hair，and inside your body，in your mouth，nose，and all through your body．

    These tiny plants and animals are called microbes．The word microbe is made from two other words：micro，meaning small，and bios，meaning life．So，microbe means small life．

    Microbes have been on earth for a very long time．They may have been the first forms of life to be alive．Today there are more microbes in the world than all other living things．

    People did not know microbes had existed（存在） long．They were too small for them to see．But people did see many changes in their world﹣important changes．And they did not know what caused them．They saw food that they kept too long change color and begin to smell bad．They saw cuts and wounds grow red and painful and become worse. They saw old plants and leaves and trees crumble apart on the forest floor and disappear into the soil．Such changes were a natural part of the world，but people did not understand them．They did not know these changes were evidence(证据) of tiny plants and animals growing all around them.

    If you want a more interesting experience when you arrive in a new city or country, here are some better ways to travel, both for you and for the environment.

    Way 1 Get out of the car and walk. It's slower but it's the greenest way to travel. It's also the most rewarding（有益的）way to see a city, but remember to wear comfortable shoes.

    Way 2 Cycling is also  a good choice. Many hotels now  offer free bikes to guests. It is convenient for people to travel around the city. Some also provide electric bikes that make it easier to go up hills and on longer journeys. Some cities also have mobikes, and you can pick up one easily. It's not free but very cheap.

    Way 3 If you have to take transport in a city, try to take public transport. Most cities now offer lots of information and very clear maps at the city's website.

    Way 4 If possible, take buses, trains or ships to travel from city to city. They are usually greener than cars and planes.

    Way 5 When the only way to travel is by car, rent(租) an electric car. Many car rental companies now offer them, so always ask!

    You must think a computer is the best thing in the world, right? You must think it works at a super speed and can do everything? Well, it's not! In fact, the brain is much more powerful than any super computer! Think about when a glass is just about to fall off the table. Your brain controls everything that you need to do to save that glass from falling. First your eyes check out what's going on, then tell your brain, and your brain decides how quickly you need to react(反应), and then your muscles(肌肉) go into action. That is just from your brain. No computer could ever come close to that!

    The brain weighs just 3 pounds, but it controls everything you do from thinking, learning, feeling even to breathing and your heart beating. Even though the brain is just 2% of your body weight, it uses around 20% of all your energy in your body. That is a lot for such a small organ(器官). There are about 100 billion tiny, tiny little cells(细胞) in your brain. There are so many that it would take you over 3,000 years to count them all!

    Your brain stops growing when you're 18, but it actually keeps on developing and learning new things. So your parents are really super smart! You won't be able to fool them! Believe it or not, your brain NEVER stops working. Even during sleeping, the brain works for long-term memory establishment(建立). It is realized that the brain is the second organ in the body as the heart that never stops during human lives.

    So everyone should be proud of such a gift of nature.

    If you do not use your arms or your legs for some time, they will become weak; when you start using them again, they slowly become strong again. Everybody knows that. Yet many people do not seem to know that memory (记忆) works in the same way. When someone says that he has a good memory, he really means that he keeps his memory in practice by using it. When someone else says that his memory is poor, he really means that he does not give it enough chance (机会) to become strong.

    If a friend says that his arms and legs are weak, we know that it is his own fault (过错). But if he tells to us that he has a poor memory, many of us think that his parents may be to blame (责备), and few of us know that it is just his own fault. Have you ever found that some people can't read or write but usually they have better memories? This is because they cannot read or write, they have to remember the things. Since they cannot write them down in a small notebook, they have to remember days, names, songs and stories. Therefore, their memory is being exercised the whole time.

    So if you want to have a good memory, learn from the people：practise remembering things as other people do.