Symbols are an important literary device that authors use to represent something abstract or invisible. In the context of "The English Patient," books, maps, and the villa all serve as symbols to convey deeper meanings.
To improve the first sentence, you can rephrase it as: "Symbols play a significant role throughout 'The English Patient' as they represent ideas that are not readily visible."
Regarding the word "affected," you used it correctly. "Affected" means influenced or impacted by something, which accurately describes how the characters in the book have been shaped by the war.
However, in the sentence about the villa, the word "prejudiced" is not clear in its context. You might want to clarify what you mean by "prejudiced" in relation to the characters' experiences at the villa.
Overall, incorporating symbols into literature adds depth and allows for deeper interpretation of the story's themes and messages.