{HEAD ~ Such catalyst systems} give {TAIL ~ both high productivity} and low solubles in the polymerization of propylene 
give
{ HEAD ~ Such catalyst systems } give { TAIL ~ both high productivity } and low solubles in the polymerization of propylene
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH