{HEAD ~ A control part} inspects the switch to produce a condition signal representative of one of {TAIL ~ the conditions} to which the switch is switched 
{ HEAD ~ A control part } inspects the switch to produce a condition signal representative of one of { TAIL ~ the conditions } to which the switch is switched
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH