{HEAD ~ The catalyst component} comprises a magnesium chloride support, a titanium trichloride, an aluminum trichloride and {TAIL ~ an organic phosphite} 
comprises
{ HEAD ~ The catalyst component } comprises a magnesium chloride support , a titanium trichloride , an aluminum trichloride and { TAIL ~ an organic phosphite }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL