What does the word “sporadic" mean

Reading journal for american literature just fill out the 10 questions 100 points

Which line from the story of my life by helen keller is an example of a simile? during the whole trip i did not have one fit of temper, there were so many things to keep my mind and fingers busy. i was like that ship before my education began, only i was without compass or sounding-line, and had no way of knowing how near the harbour was. one day, while i was playing with my new doll, miss sullivan put my big rag doll into my lap also, spelled "d-o-l-l" and tried to make me understand that "d-o-l-l" applied to both. child as i was, i at once felt the tenderness and sympathy which endeared dr. bell to so many hearts, as his wonderful achievements enlist their admiration.

Read the passage, then use the explanation to infer the meaning of the word predominant. the novel was so popular that it was eventually added to a list of books that every ninth grader had to read. it became the predominant work of literature. what is the most likely definition of the word predominant?