{TAIL ~ The number} of metallic probes can be controlled to thereby control the amount of {HEAD ~ metallic ions} produced 
{ TAIL ~ The number } of metallic probes can be controlled to thereby control the amount of { HEAD ~ metallic ions } produced
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH