Проверьте, пожалуйста, текст на наличие ошибок I39;d like to tell you

Проверьте, пожалуйста, текст на наличие ошибок I39;d like to tell you about Steven Hawking. He39;s a famous physicist. He first studied at Oxford. Then he began to study at Cambridge, where he became Professor of mathematics. Studied the theory of the origin of the world in a Big Bang. Also studied the theory of black holes. 30 years ago the doctors said he had only 2 years. Soon, he was paralyzed. After a serious illness he had lung problems. Later, Hawking has lost the ability to speak. Friends gave him a speech synthesizer that was installed on his wheelchair. Now Stephen 73 years. Despite his illness, he leads an active lifestyle. April 26 2007 he flew in zero gravity . 2009 was a scheduled flight into space, which did not take place.