Cai Lun invented paper around 2，000 years ago in China. It is an important invention. Before the invention of paper，people had to remember lots of information or write it on stone，wood，leaves，etc.
Today everyone in the world uses paper. With paper，we can make books and print newspapers. Sharing information is a lot easier with the help of paper.
People use paper every day. Students do homework and keep a diary on paper. Paper is a great invention.
Alan Turing was born in London，England，in 1912. He attended Cambridge University from 1931—1934. Turing was a mathematician（数学家）and a computer scientist. Many people called Turing the father of computer science. He created the first design（设计）for a modern computer.
Turing wanted to know if a machine could think for itself and trick someone into believing they were having a conversation with another person. This became known as the Turing test. In the test ，a human talked to two other people through a computer. One was a machine and the other was a person. This idea is still used today.
