Ding-dong! ding- dong! the bells rang all day long. what is the example of this?

The answer is "onomatopoeia." Onomatopoeia are words the mean a action but are being repeated. I did a lot of research on context clues and this is a big one. Onomatopoeia is used in story to show a action on a object for example (in your question) the bell. Bells go Ding-dong but when they are repeating the sound "Ding-dong! Ding- dong!" that's a example of onomatopoeia.

Hope this helps!