x1=tcit1=s3 is a modal (BAI, «fi'o broda», PU, etc.) of/based on/derived from x2=tcit3=tcin1 (e.g. «bai», «se cabna» ({se} used for tense)) for sumti x3=tcit2=s1 of selbri x4=s2.
hybrid {be} and {bei}: sumti link to attached sumti to a selbri, repeatable, valid for both first and subsequent attachments.
Can also appear immediately after gadri like {lo}.