Solution

Derry sneaked into Mr Lamb’s garden and it became a turning point in his life. Before that, Derry used to live an isolated life. He did not like meeting people or socializing. The reason was his acid-burnt face, seeing which people often got terrified. He began leading a secluded life.
Meeting Mr Lamb brought a change in his life. His attitude towards life was completely changed. Mr Lamb gave him confidence and supported him morally as he was too physically impaired like him. He had a tin leg because the original one was blown off in the war. He told Derry that he was not affected by people’s sarcastic remarks. He motivated Derry to face the challenges of life and not to lament over his burnt face. According to him, he was lucky to have two arms, two legs, ears, eyes and a tongue. He could do far better than others.
All these preachings left an impression on Derry and then he started looking at things and the world differently. He began to help Mr Lamb with crab apples and developed a positive attitude towards life.