The rate of hardening, or polymerization, of adhesive can be controlled by varying {TAIL ~ the concentration} of {HEAD ~ catalyst} in the catalyst solution 
The rate of hardening , or polymerization , of adhesive can be controlled by varying { TAIL ~ the concentration } of { HEAD ~ catalyst } in the catalyst solution
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH