A student evaluating an expository text should

be critical in assessing the contain that is in the text.

Expositiory are based on facts or good sources / opinionated personas. As oppose to narrative writing, narrative writing may be found in the form of drama, prose and poetry but it is not "only" fictional. Many writers write narrative texts based on the non-fictional events in their own lives. As fiction is the literature related to imaginary events and people, this statement becomes NOT true.