Please pay attention to the in the lab.

    We are lucky to live in a rich country where we have many things. However, most of us usually (waste) some things.

    Electricity is one thing that we waste most. Lights, TVs, (radio) and other things are often kept on even when no one is using them. We should turn them off we do not need them. It takes   (little) than a second to do it. Anyhow, not wasting electricity saves money, because we do not have to pay for the electricity we do not use. The (two) thing that we often waste is water. Fresh water is precious, so it shouldn't be wasted. It is only a simple matter of turning a tap. I am sure everybody can do this (easy) if he wants to. Another big waste is food. My mother used to cook so much food that much of it was thrown away. I told her we had wasted so much (food). She thought I was right and now cooks mainly what we can eat.

    It is not right to be wasteful. I find there is a simple way of not wasting things. That is (use) only what we need. Do not touch what we do not need. this way, we can stop being wasteful.

    Do you know what makes lightning (闪电)?

    Lightning strikes happen when ice and water in clouds rub (摩擦) together, and cause atmospheric (大气层的) changes. When this happens, it creates a static charge (静电). Lightning can strike inside the cloud, between two clouds or between a cloud and the earth.

    Lightning can be very dangerous. Every year, lightning kills people because it can start big fires or because it reaches a temperature of 28,000℃. About 1,000 people are hit by lightning every year in the United States, and about 100 of them die as a result.

    Scientists think that there are more than three million lightning strikes every day in the world. An American man, Roy Sullivan, who worked in a park, survived from the most lightning strikes. And he keeps the highest world record.

    Lightning is sure not something to play with. When lightning strikes, it's best to stay inside a large building. Also, do not lie down on the ground, or the electricity may go through you and cause a heart problem.

Using electricity safely

    Electricity is an important part in our life. We can't see or touch it, but it is all around us. Our life will be terrible without electricity. But some people don't know that everyone should save electricity. When it is not completely dark, many street lamps (路灯) light up early in some streets. Some people don't turn off the lights when they leave the room. Some people are sleeping with the lights on. They are all wrong. Here I make some suggestions about stopping these things:

    *Turn on the street lamps on time. We light them from 7：00 p. m.～5：30 a. m. in summer, and from 5：30 p. m.~6：00 a. m. in winter.

    *If some small areas are very dark, just turn on a few lights.

    *The distance (距离) between street lights can be 50～60 meters. It can save electricity and money.

    *If there are some activities, such as fairs, we can make the lights bright；if there is no activity, lights needn't be too bright.

    Ask people to save electricity through TV shows, newspapers, and so on.

    Electricity is a valuable resource (资源). It helps us live well and conveniently. We should take action to save it at once!

—Yes, but he has no time to reply.