Finding a real gap
A gap is not “nobody has studied this” — that is rarely true and hard to prove. Common, defensible gaps are a population not yet studied, contradictory findings, an outdated evidence base, or a method that has not been applied.
State the gap with evidence: cite the studies that reveal it.
Example
“Although engagement in blended courses has been studied in Western universities (refs), evidence from Gulf institutions remains limited to two small studies (refs).”
Exercise
In your literature review section, draft one sentence stating your gap with citations.