Our reporter asked people what they were doing on July 20th, 1969 when man first walked on the moon. Here is what they said:

Kate Jones, waitress I remember that day very well. I was fifteen years old. It was a hot and humid day, and I was with my family in the mountains. We were having a picnic. We didn’t see the moon landing when it happened, but we were thinking about it. We saw it later on the TV news.

John Bates, postman I was eighteen years old. It was a very exciting day. I was watching TV at home when the astronaut walked on the moon. His name was Neil Armstrong. I remember he could jump really high because people aren’t so heavy on the moon. When he returned, he became a national hero in America, and famous all over the world.

Paul Robinson, doctor I was twelve. I remember the day, but I don’t remember what I was doing. I remember I wanted to go to the moon, too. My dream was to become an astronaut and fly in a rocket. I wanted to see the earth from the moon. The astronauts on the moon said that the earth looked very beautiful from there.

Linda Brown, clerk I was working that day. I was twenty then. I didn’t see the man land on the moon because I was busy. Of course I knew about it. I read about it in the newspaper the next day. I thought it was amazing. Maybe one day people will travel to the moon for vacations!

Mark Green, teacher I was only seven years old then. My parents talked about it, and I learned about it later in school, but I don’t remember the day. I was too young to remember. Maybe I was having fun in the playground with my friends when it happened.

It is widely agreed that the overuse of coal and oil has caused serious environmental problems. Scientists are trying to find new clean energies that do not pollute the air, the water or the ground. Solar power(太阳能)is one of them.

Solar power is a kind of electricity which is produced by taking energy from the sun, using solar panels(面板，电池板). The power is easy to get and will never be used up. Whenever it is sunny, there is the power. The power is clean and renewable. It helps to reduce waste and pollution, which is great for the environment. For some areas that are too far away to send electricity to, solar power is especially necessary. People there use solar power for lights, TVs, computers, washing machines, fridges and many other things.

Therefore, more and more countries, such as China, the USA, Japan and India, encourage scientists to develop practical(实用的)technology to put solar power to use. However, the power is not as widely used as expected(预期的).

One of the challenges(挑战)is that a solar power system needs sunshine. Countries or areas with a lot of rain, like the UK, are not suitable to develop such power systems(系统). Secondly, a solar power station requires a very large site(地点)to fix(安装)enough solar panels to collect sunlight and change it into electricity. What’s more, solar panels are expensive at present though the energy itself doesn’t cost anything.

Today scientists are working hard to develop more practical and cheaper solar power systems. Maybe one day solar power will be one of the most important clean energies in our life.

If someone asks you, “What colour is the sky?” I think you will answer “blue”. I’m afraid that you are wrong. The sky has no colour. It looks blue because we are looking at the blue sunlight. It is shining on little bits of dust (灰尘) in the air.

Is the sky full of air? I’m sure that you have asked this question, too. We know there is air all around the world. But we couldn’t fly very high because as we go high, the air gets thinner (更稀薄的). If we go far enough (足够的) away from the earth, we find there is no air.

Maybe we can answer some questions now. What is the sky? Where is it? The sky is space. It’s all round the world. In space there is nothing, but only the Sun, the Moon, the Earth and all the stars.