Because of a change of assignment, the couple were not able to continue the study. But they were able to visit this town 25 years later.
ثُمَّ طَرَأَ تَغْيِيرٌ عَلَى تَعْيِينِ ٱلزَّوْجَيْنِ مَنَعَهُمَا مِنْ مُتَابَعَةِ ٱلدَّرْسِ .‏