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    When you build a house，you use a blueprint．What's a blueprint?In general，a blueprint is a drawing that you use to build a house and shows where to put all the parts of the house．DNA is a drawing,too．It's the blueprint of life．

    But building a living thing is far more complex*than building a house．It takes millions of years for nature to change the DNA in living things to make them fit the world they live in．

    How tall are you?What color are your eyes?What size are your feet?All these things are strongly influenced by your DNA before you are born．

DNA is fantastic!

  ★Except for some twins，every living thing has its own unique*DNA．

  ★Some health problems can be caused by problems in your DNA．Scientists can look for these problems and，sometimes，help you if you become sick．In the future，scientists might be able to change your DNA．   

  ★There are copies of your DNA in every part of your body．For example，your finger has the same DNA as your hair．

  ★You have your own unique DNA，which repeats patterns from your parents' DNA．but not exactly the same．From your DNA，scientists can identify not only you，but also people who are related to you．Your parents and grandparents are related to you，and you have their DNA．When you have a grandson or granddaughter，he or she will have your DNA．

    Your DNA has billions of instructions that explain why you are the way you are．It's one of the most amazing things on the earth !

    Only humans speak using words. But all kinds in the animal world can communicate in one way or another. Maybe you have heard about the way bees dance around to send messages to each other and the way dogs bark in different ways to give warnings, to be friendly or to be playful. But did you know about infrasonic communication used by elephants? This is how it works:

    Humans hear low sounds like thunder rumbling in the sky. But we don't hear sounds lower than this. However, animals such as elephants and hippos can hear much lower sounds than humans can. And what's more, they can make those low sounds as well, and they use them to communicate with each other. This is known as infrasound.

    The amazing thing about infrasound is that it travels over several kilometers. Higher-level sounds like the one people can hear, don't travel well through walls, leaves, trees and so on, which is why we can't hear sounds from more than 100 meters away. But infrasound is much stronger and things like grass and trees have no influence on it. Therefore, it can travel much further. Elephants can hear infrasonic calls from four kilometers away!

    There have been reports of people watching groups of elephants feeding or resting and then the elephants suddenly all stopped what they were doing for no reason at all. They obviously heard a warning call from a long way away, but the people didn't hear a sound. In places like a zoo or wildlife park where you can get nearer to animals, it is a bit easier to sense when infrasonic sounds are made. When you stand near mother elephants with their babies in a zoo, you may notice a slight rumbling in the air every few minutes—not loud or strong, but clearly noticed. This is infrasonic communication—the mother elephants “talking” to their babies.

    Drinking water is good for your health. There are some scientific ways of drinking water.

    ⒈It is the best medicine to drink two glasses of water in the morning.

    ⒉Drink clean water.

    ⒊Drink the water that has not been boiled.

Many people think boiled water is safe and good for people's health. In fact, it is not true. The boiling point of water is 100 ℃. By boiling it, most bacteria(细菌) in water can be killed. In the past, the water was less polluted, so boiling was a good way to make clean water. But heavy metals and other dangerous things in today's water are much more terrible than bacteria. Boiling doesn't solve that problem. And boiling water may give us more dangerous things in our glass.

    ⒋Never use soft drinks to take the place of water.

    ⒌Water is also needed in winter.

    ⒍Drink water at the right time.

    1) After getting up in the morning, you have less water in your body, because you weren't drinking for the whole night .So you should drink some water to keep your health after getting up in the morning. That can prevent high blood pressure(血压), cerebral hemorrhage(脑溢血) and so on.

    2) Drinking water at about 10 a. m. helps your body keep enough water.

    3) Drinking water at about 3 p. m. can clean the wastes out in your body.

    4) About eight o'clock in the evening is the best time to drink water. Your blood gets thicker when you sleep. Water will make your blood less thick.

    Besides, we should drink 2L of water every day. Water is so important in our life. We should drink water often.

    When on the go or traveling, a Disposable(一次性) Toothbrush might be just the product for you, Typically, a Disposable Toothbrush is made out of a plastic material, with toothpaste already on the brush head. Just add water while you are using it. In some new Disposable Toothbrush models, the toothpaste comes automatically(自动地) as you squeeze (挤) the handle of the toothbrush.

    Colgate has upped the competition in the Disposable Toothbrush market by creating a Disposable Toothbrush that you can use at your desk at work, in your car, or after eating at a restaurant. This toothbrush is called the Colgate Wisp, and is about the size of an index finger. The toothbrush can get to those places that are hard to reach just like a regular toothbrush. No water is necessary when using this toothbrush, making it very useful and convenient. A pack of four of the Colgate Wisp's run at about $2.99. If you are one of those people that like to brush your teeth throughout the day but hate the hassle of carrying a toothbrush and toothpaste around, this is perfect!

    Gadgets.boingboing.net is a website that allows different people to share their thoughts and experiences on a certain product. The website gives a general review on the Colgate Wisp，and following the review, people are able to share their first-hand feelings with readers. This is helpful if you are interested in purchasing the Wisp. Visit their website here: gadgets.boingboing.net.

    However, people throw them away after using them only once. It is a kind of waste and is very bad for the environment. If you travel to Beijing， remember to bring your own things. Starting from June, some hotels in Beijing will no longer provide guests with these disposable goods.

    My parents often take me to the zoo at weekends. I like animals. I have many toy animals in my room. In the zoo I can see tigers, elephants, pandas and many other animals. Some animals are friendly, but some are not. Tigers, lions and snakes are dangerous. That is why they have to be in the cage. But I think it is terrible for animals to be in the cage.

    Tigers usually live in forests and mountains. They can run. They catch and eat small animals, but now they live in small rooms. They can only walk and sleep in the cages, and they want to go out. I feel sorry for them.

    I think my favourite animals are dolphins. I like watching them swim and jump. They can play with a ball. They can "walk" on the water! They are very friendly to people. They can help you when you fall into water and can't swim.