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