Answer:
This passage is effective at conveying Roderick's madness by using repetition.
Step-by-step explanation:
The use of a repetition is a very effective tool in a story to demonstrate the madness of a character.
In this case, after the death of his twin sister, Usher's attitude became totally strange and began to show signs of mental disorder.
In this excerpt, what is done is to emphasize that madness through the continuous repetition of words. Acting like a madman, Usher begins to say that he listened to something all for a long time, every hour and every minute.
What she heard was her sister's voice and assured that she had been buried alive.