means for receiving {HEAD ~ a scenario} for specifying an execution sequence of {TAIL ~ knowledge sheets}; and 
means for receiving { HEAD ~ a scenario } for specifying an execution sequence of { TAIL ~ knowledge sheets } ; and
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH