A conjunction can be placed after the comma to make the sentence make sense (i.e. and, so, ect).
An interjection can be more than one word
<span>Narrative poetry is a form of poetry which tells a story, often making use of the voices of a narrator and characters as well; the entire story is usually written in metered verse. The poems that make up this genre may be short or long, and the story it relates to may be complex.</span>
I believe it's being able to write for various contexts. It'll help you become a better writer.