When execution of the communication task can be extended, {HEAD ~ the communication apparatus} extends {TAIL ~ execution} of the communication task to a later time 
extends
When execution of the communication task can be extended , { HEAD ~ the communication apparatus } extends { TAIL ~ execution } of the communication task to a later time
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH