下列各句均有一处错误,请找出并改正。 ( )1. The boy is good at play football. A B C D ( )2. He often plays a piano A B C D ( )3. He is born in Beijing A B C D ( )4. When did he start sing ? A B C D ( )5. He became a player at the age eighteen. A B C D _______ _______ _______ _______ _______