Otherwise, {HEAD ~ the present system} applies {TAIL ~ additional candidate transformation rules} to the selected query element to generate the transformed inexact query output for querying the heterogeneous datastore 
applies
Otherwise , { HEAD ~ the present system } applies { TAIL ~ additional candidate transformation rules } to the selected query element to generate the transformed inexact query output for querying the heterogeneous datastore
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH