Mr Chen has a computer shop. He can do so many things with computers， such as writing letters， drawing pictures， adding up numbers and playing games. He can use them to send messages to other computers. Some people use big computers to send rockets into space.

Computers are much better now than before. They are also much smaller. Forty years ago one computer was as big as a small house. Today computers can be quite small. You can carry a small computer in your schoolbag.

A computer has a keyboard and a screen. The keyboard has all the different letters and numbers. The screen is like a television. You type words on the keyboard. You use a mouse to do things like drawing pictures. You can read the words or see the pictures on the screen. A computer can keep the things you do in a floppy disc（軟盤）.

More and more new types of computers are invented. People like iPhone and iPad very much because they are the excellent computers by now. Computers are getting cheaper and cheaper and they are necessary for each family.

Today people can use the phone to talk with others almost anywhere on the earth. But when you use the phone， you dont see the person you are talking with. That may change in the near future.

Today some people are using a kind of telephone called the picture phone or vision phone. With it， two people who are talking can see each other.

Picture phones can be useful when you have something to show the person youre calling. They may have other uses in the future. One day you may be able to ring up a library and ask to see a book. Then youll be able to read the book right over your picture phone. Or you may be able to go shopping through your picture phone. If you see something in the newspaper that you think you want to buy， youll go to your phone and call the shop. People at the shop will show you the thing right over the phone. Youll be able to shop all over town without leaving！

Is it possible to send messages to someone anywhere in the world without putting a stamp on it？ Its easy to do so. Using computers you can send emails quickly and easily. If you have an email address， you can write， send and receive messages.

Email is the most inexpensive way to communicate（溝通）. You can send messages at any time of day or night all over the world without paying for a long distance call. Many companies use emails for people in their offices or in other offices to communicate with one another. You can send the same message to fifty people or more. It doesnt matter if your friends are in bed when you send email to them， or you are seeing a movie at the cinema when they send emails back. Many schools and universities give email addresses to their students. Email addresses are becoming as common as phone numbers， but they can also make our lives more complicated（復雜）.