There are many kinds of trees. All trees have roots. The roots hold trees in the ground. The roots soak up ( 吸收 ) water and food. Then trees get water and food from the roots. You can't see inside a tree. But you can study how water moves through trees.

    First, get a stalk ( 茎 ) of celery ( 芹菜 ) and cut off its end. Put red colour in a cup of water. Then put the stalk of the celery into the red water. Then we can see the red water moving up in the celery easily.

    After half an hour, take the celery out. Cut it in half. Your celery should be red. This is because the water moved up the stalk. Water moves through trees in the same way as it moved through the celery.

    What isthe hardest sport in the world? Some people say it's boxing (拳击), because boxing is dangerousand boxers have to be strong and fast. Other people say the hardest sport issoccer.

    However,most people say the hardest sport is the triathlon (三项全能运动). A triathlon is a race thatincludes three sports. First, racers swim. After that they ride bicycles andfinally they run. In the most common triathlon, racers swim 1.5kilometres, bike40 kilometres, and run 10 kilometres. The winner is the person who finishes therace first.

    There isanother kind of triathlon too. It is called the "Ironman Triathlon (铁人三项)". This triathlon is muchlonger. People who finish this triathlon are called "ironmen" or"ironwomen". This is because these people are so strong that theirbodies are just like iron (铁).

    In thepast, there were other races including three sports. However, they didn't usethe word "triathlon". That word was first used to describe a race inCalifornia in 1974.

    Triathlonracers have to train very hard for their races. Many of them swim and run. Alot of people also do things like yoga (瑜伽). They have many different ways to prepare, but they all have thesame goal. They want to be in perfect shape.

    To be anironman or an ironwoman, you have to be strong and smart. You should know howto save energy during the race.

There are many colors in nature. But do you think that a color has weight? Let's do a test.

First, put two objects with the {#blank#}1{#/blank#} weight into two boxes. Then cover the boxes. Third, wrap (包裹) one box with a red piece of paper, the other with white. Now hold the boxes {#blank#}2{#/blank#} your hand one by one. Which one is {#blank#}3{#/blank#} ? It is certain that you will think the red one is heavier. Why do you think so? A scientist did many {#blank#}4{#/blank#} and found that different colors have different weights in a man's mind.

Also, scientists say that people accept the colors they like, and {#blank#}5{#/blank#} the colors they hate. So your body and mind will be {#blank#}6{#/blank#} by using the colors you like. Or you'll be nervous {#blank#}7{#/blank#} even get ill. For example, you {#blank#}8{#/blank#} blue and hate red. If you stay in a room with red windows and wallpaper for two hours, you'll feel you have been there for {#blank#}9{#/blank#} hours. But if the room is blue, you'll feel you have been there for only an hour, And, if a person walks {#blank#}10{#/blank#} of a blue room and into a red room, his temperature will rise. That means our body temperature will change with different colors.

"I want to know how to speak English well.{#blank#}1{#/blank#} can I do?" Bill asks this question like many students do. I ask{#blank#}2{#/blank#}(he),"How do you learn English?" He {#blank#}3{#/blank#}(answer),"Only in English class." {#blank#}4{#/blank#}first thing I will say is, "That is not enough!"

If you want to speak English {#blank#}5{#/blank#}(good), you have to practise. Speak to friends, classmates, people online or in stores. Speaking is the best way {#blank#}6{#/blank#}(learn) a language.

In my class I usually ask my students how they feel {#blank#}7{#/blank#} speaking English, and they often say "nervous", "scared" or some words like these. The {#blank#}8{#/blank#}(two) piece of advice I can give is to relax. Don't worry about making {#blank#}9{#/blank#}(mistake). If you can't think of the right word to use, don't worry about it and just say what you want to say.

Speaking English well isn't just about practising your {#blank#}10{#/blank#}(speak). It is also important to listen to English. Listening to the English songs and English tapes is helpful.

As a country strong in math, China has many folk games filled with math wisdom. You may have played many of them before. Let's take a look at two of them. 

Title: Two Ancient Chinese{#blank#}1{#/blank#} Toys