Therefore, {HEAD ~ production} of {TAIL ~ the nozzle} is easy, and its production cost is low 
of
Therefore , { HEAD ~ production } of { TAIL ~ the nozzle } is easy , and its production cost is low
OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH