18、George Stephenson was born in 1781. He was _ _ 21 _ _ a poor English worker's family. His father looked after a steam engine. He worked hard indeed, _ _ 22 _ _ he could not support his family. Where could he get the money to send George to school? George began to learn his ABC when he was seventeen. On his 18th birthday, he could write his own name.
George had to work when he was only a small child. The work was much too hard _ _ 23 _ _ him. He worked for 12 hours every day. After a day's work he often felt _ _ 24 _ _ tired to stand.
He worked and studied very hard. He spent all this time learning about the steam engine.
_ _ 25 _ _ he studied hard, he invented many things. The railway locomotive（火车头）was the greatest one of them.