Ordinarily, mineral lubricating oils are used by {HEAD ~ reason} of their availability, general excellence, and {TAIL ~ low cost} 
of
Ordinarily , mineral lubricating oils are used by { HEAD ~ reason } of their availability , general excellence , and { TAIL ~ low cost }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL