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