Answer:
Listeners benefit from listening:
(i)When the narrator emphasizes key words ,
(ii)when the narrator pauses for effect, and
(iii) when sound effects are used.
Explanation:
Generally, when the narrator emphasizes key words then he wants the listeners to benefit more by listening to what he is emphasizing on for future usages. Also, when the narrator pauses during a lecture or presentation, he hopes the listener could digest what he has just said and would be able to save it to memory for future uses.
When sound effects are used in a lecture or presentation by a narrator, the listener tend to benefit more because the sound takes the better part of the listeners sense of hearing and thus enhances listening and comprehensions.
These three are the best options for the listeners to benefit when listening to a narrator during a presentation or narration to the audience.