What is restricted in “mā intafaʿū ... illā ḥīna aḥsanū qirāʾatahā”?

Supplementary Practice 8: Rhetorical Analysis of Five Connected Passages

• Exclusion of everyone other than these students
• Restriction to a particular book among books
• The time or condition in which these students benefited
• Restriction of the opening time rather than benefit