Long, long ago people made fires from lightning (闪电). But they had to keep the fire burning, for they couldn't start it again if there was no lightning. Later, they found out hitting two pieces of stone together could make a spark(火花). The spark could fire dry leaves. In this way they could make a fire again if it went out. Then people also learned to make a fire by rubbing(摩擦). They made a hole in a piece of wood and put a smaller stick into the hole. They turned the stick again and again. After a few minutes they got fire.

    Years went by, people learned other ways to make a fire. Sometimes they used the heat from the Sun. They held a piece of glass in the right way and made a piece of paper on fire.

    About two centuries ago, people began to make matches.  Matches brought people a quick and easy way to make fires. Today matches are still being used, but people have more new ways to make fires. One of them is to use an electric fire starter. Of course an electric fire starter is much more expensive than a box of matches. But it is very useful.

提示：1）我们手湿时，不能触碰电器；

2）电器不能工作太长时间，我们应该让它们休息一下；

3）不能让小孩触碰电器，比如微波炉等；

4）当我们清洁或者修理电器时，一定要先切断电源。

    Do you know the way of using wind power to make electricity? There are many advantages({优点) of using wind to make electricity. Here're some of them.

    First, it may be one of the cheapest ways to make electricity. Second, it can make and store hydrogen gas. The most important one is that it won't pollute the environment. Besides, the wind power can be reusable.

    But large wind farms might kill birds too, because birds always fly into the wind turbine(风力涡轮机). Scientists are looking for ways to stop it.

    Experts said that by the middle of the 21st century, wind power could supply more than 10% of the world's electricity. Wind really helps us a lot.

    Summer is just around the corner. It starts on June 21^st or 22^nd. For most kids, that means more time to play outside and have fun. Follow these tips to make sure you stay safe when you are enjoying the season. Sun safety

    Many kids will spend hours playing outside in the summer dun. But be careful. The harmful rays(光线) of the sun can cause damage to your eyes. If you are out in the sun, be sure to wear sunscreen(防晒霜). You should also wear a hat and sunglasses that protect against the harmful rays.
    __________

    Make sure you follow water safety rules. Always swim with an adult watching you. If you don't know how to swim, you can take lessons. Rules about biking and skating

    Biking and skating are good ways to exercise. To stay safe, always wear a helmet(头盔). It will protect your head if you fall down.

    When you watch TV and play video games you make global warming(全球变暖) worse! To make electricity, fossil fuels(矿物燃料) are burned in big factories. But burning fossil fuels also makes greenhouse gases. This means that every time you use electricity you help make global warming worse!

    Cars are also making global warming worse. They burn fossil fuels in their engines, and send lots of greenhouse gases into the air.

    So what can we do to stop global warming?

    Try to use less electricity. First, turn off lights, your television, and your computer when you stop using them，You could also try to watch less TV. But you may find it hard to do these! Second, plant trees. Not only is it a fun thing to do, but it is also a great way to lower the number of greenhouse gases in the air. Trees take carbon dioxide(二氧化碳) out of the air when they grow. Last, don't throw away your rubbish, but try to recycle it. Because if rubbish is not recycled, it rots(腐烂) and makes a greenhouse gas called methane(甲烷). So try to recycle cans, bottles, plastic bags and newspapers. It'll make you feel great! And it'll help the Earth.

    Electricity is a type of energy that was discovered over 100 years One of the most common  (way) to make electricity is changing other energy sources(来源), such as coal, oil, solar, wind  falling water. You may not even realize that electricity is a huge part of  (you) everyday life. Basically, it (keep) your home and school warm in winter and cool in summer. Without it, you would never  able to watch your favourite TV show or listen to your MP3 player. Have you ever imagined a world in which you can't  (turn) on a light, a computer, or even use the phone? So electricity is (importance) to us and we need electricity.  That's why it's time to rethink (us) relationship with the valuable resource and think about how we can do our part in  (use) it wisely.

— All right.

— Maybe she didn't pay attention to the questions.

— No, I think you make a mistake.