I think the greatest invention is the computer.

First of all, computers shorten the distance of people. In the past, people sent letters to each other by pigeons. This method took a long time and there might be a failure in delivery. Now we can send e-mails through computers. It only takes a few minutes to pass the message to someone who is far away.

Secondly, computers help us work more efficiently. We can save a large amount of data in the computers. We also have the right to update and use the data whenever we need.

Thirdly, computers create new ways of entertainment for people. People enjoy playing computer games, listening to music and even watching the new films with the computers. This reduces pressure and help people relax from work.

Fourthly, computers can process a great amount of data in a very short period of time. Many scientific researches need to deal with large amount of data. These take a lot of time for people to organize and analyze the data. Nowadays, all these can be done by the computers. This saves time.

To conclude, I think the invention of computers is a great revolution.