Alternatively, {TAIL ~ scenarios} may be provided by {HEAD ~ a user} or obtained from another source 
Alternatively , { TAIL ~ scenarios } may be provided by { HEAD ~ a user } or obtained from another source
OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH