It is very important that the parts do not come apart after {HEAD ~ the training device} has been assembled for {TAIL ~ use} 
assembled for
It is very important that the parts do not come apart after { HEAD ~ the training device } has been assembled for { TAIL ~ use }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL