{HEAD ~ This mixture} is then contacted with {TAIL ~ the remainder} of the electron donor or transition metal component for a second contact time of less and 110 seconds 
{ HEAD ~ This mixture } is then contacted with { TAIL ~ the remainder } of the electron donor or transition metal component for a second contact time of less and 110 seconds
HEAD HEAD HEAD HEAD HEAD HEAD REL OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH