The toy that saved a life 
Group 1, Students: Emilio , Aurora, Jaime
Text:
One day, a  man went to a  pub. There were some  guys playing a  game of darts. He joined the  game [The game that the gays were playing. (You) ✓, The game that the guys were playing (Harry)]  and won.
The  prize [The prize that the guy won. (You) ✓, The prize for winning the game (Harry)]  was a  toy stethoscope. 
He was playing with the  stethoscope [the stethoscope that the guy was playing with. (You) ✘ - this is a circular explanation: He was playing with the stethoscope that he was playing with. You need to refer to something that we already know to make the stethoscope specific., The stethoscope that he won (Harry)]  and decided to listen to his own heart. He heard a  strange noise: two quick beats and then  the  slow one. He was worried. He left the  pub [The pub were he was. (You) ✓, The pub where he won the stethoscope (Harry)]  and went    home. 
He went to a  doctor the next day. 
The  doctor [The doctor who the guy visited. (You) ✓, The doctor that he went to (Harry)]  did some  tests and found out that the  man [The man who have been visited by the doctor. (You) ✘ The man visited the doctor. The doctor didn't visit the man , The man who went to the doctor / won the stethoscope / went to the pub... (Harry)]  had a  hole in his heart. He told him that he needed an  operation to close the  hole [The hole that the doctor found out in his heart. (You) The hole that the doctor found in his heart (find is for things, find out is for information – so you could say: The hole that the doctor found out about.), The hole in his heart (Harry)] . 
He had the  operation [The operation that the doctor told him that he needed. (You) ✓,  (Harry)]  and is fine now. A  stethoscope saved my life!"