Interpretation

Understand what the author is trying to say, known as Explication. Analyzing line by line the text something i never seem to quite very well intrepret, could it be beacause iam not reading the text correctly or because that is my own intrepretation of what he or she was trying to say. Is there a right or wrong answer? i wounder. Example, when we where put in groups and given a poem to define my interpretation of LONDON by Willaim Blake was the opposite of what the rest of my classmate came up with. I though it was about a women who had a disease and was passing it to everyone in the village and thats why everything was dark. I made this decision when he said " most through midnight streets I hear how the youthfull Harlot's curse". The sadness " In every cry of every man, In every infant cry of fear". In reality its about how one man depress see the world.