Many people regard Albert Einstein(1879-1955) as one of the 20th century's greatest geniuses. His attempt to explain the working of the universe helped create such things as nuclear energy,space travel and television. The modest Einstein used to say that the only gift he had was curiosity,but stories about him show that he also had a sense of humour. One tells that, as a young man with a growing reputation he received many invitations to go to universities to explain his theories. On these trips, his driver was always the same a man called Hans. Hans often said to him, 'It's a pleasure to drive a genius like you, Dr Einstein One evening, on their way to a remote university, Einstein said'I wish I didn't have to give my lecture tonight, Hans. I'm so tired.But I can't let my audience down, can I? You don't need to said Hans. 'We'll change places and I'll give the lecture for you. I've listened to it dozens of times.I don't understand it but I know it by heart And no one knows you at the university do they? No one will find out. Einstein eventually agreed with Hans, but said to him'Don't try to answer any questions whatever you do. They changed places and at the university Hans was greeted and led to the platform of a great hall crowded with professors and students. Einstein took a seat in the audience listened to Hans give his lecture perfectly and joined in the applause at the end. However, before Hans could get off the platform a professor shouted from the audience'I'd like to ask you a question. It's very difficult but please answer it. He then asked a question so difficult that Hans had no idea what he was talking about. Einstein thought Oh dear, now we're in trouble. But Hans just laughed and said, That's not a difficult question sir. In fact, it's so easy even my driver knows how to answer it. Hans, stand up and ...Einstein stood up and answered the question perfectly They left the university, with Einstein driving. A little later, Hans offered to take over from him. 'No, my friend.'laughed Einstein. 'It's a pleasure to drive a genius like you, Hans.'