The sun provides sunshine for plants, animals, and people here on Earth. Energy from the sun is called solar energy. It comes in the form of light or heat. Solar energy makes you feel hot. People have used solar energy for thousands of years. Houses were built with windows so that sunlight can get inside and provide heat. The sun’s energy can also be used to heat water and even food.

We can also turn the sun’s light into electricity. This is done with solar panels(太阳能电池板). Solar panels are made up of silicon(硅). When the sunlight reaches the solar panel, the electron(电子) in the silicon, moves and flows through wires in the solar panel.

Using this technology, we can run even cars. But what happens when clouds block the solar panels? The electrons in the silicon will stop moving. But this doesn’t mean that solar energy can only be used on bright sunny days. Solar panels can have batteries to store(储存) electricity for a rainy day. When the sun is shining, the electricity flows from the solar panel into the batteries. This stored electricity can be used at night or on cloudy days.

Solar energy is not as expensive as before. The sun produces more energy in one second than people have used since the beginning of time. Just imagine what we could do if we used the sun’s energy to power our Earth.

Real policemen can hardly tell any similarity between their lives and what they see on TV.

The first difference is that a policeman’s real life is almost around criminal law. He has to know exactly what actions are crimes and what can be used to prove someone guilty and lead him into prison. He has to know nearly as much law as a professional lawyer, and what is more,he has to apply it on his feet, in the dark and rain, running down a street after someone he wants to talk to.

Little of his time is spent in chatting. He will spend most of his working life typing millions of words on thousands of forms about hundreds of sad, unimportant people who are guilty of stupid crimes.

Most television crime drama is about finding the criminal:as soon as he's arrested, the story is over. In real life, finding a criminal is seldom much of a problem. Except in very serious cases like murders and terrorist attacks, only a little effort is spent on searching.

Having made an arrest, a policeman really starts to work. He has to prove his case so that he often has to look for a lot of different clues.

A third big difference between the drama policeman and the real one is the unpleasant pressures: first, as members of a police force, they always have to behave completely according to the law. Secondly, as expensive public servants, they have to get results. They can hardly ever do both. Most of the time some of them have to break the rules in small ways.

If a policeman has to deceive the world, the world often deceives him. Hardly anyone he meets tells him the truth. And most policemen feel the separation between themselves and the rest of the world is deepened. Most citizens, social workers, doctors, law-makers, and judges are in some ways simple-minded, they suggest not punishing the criminals in a very strict way in the hope that this will make them reform. The result, most policemen feel is that nine-tenths of their work is re-catching people who should have stayed prison. This makes them feel rather bad.

Most English people have three names: two given names and a family name. The family name is the last name. My name is Linda Susan Baker. Linda is my first name. It’s a given name, too. My last name is Baker. People can call me Linda or Miss Baker.

In China, the first name is the family name, and the last name is the given name. A man’s name is Wang Tao. Wang is his family name and Tao is his given name.