When a request for communication task is detected, the communication apparatus determines whether {HEAD ~ execution} of the communication task can be extended at {TAIL ~ a later time} 
extended at
When a request for communication task is detected , the communication apparatus determines whether { HEAD ~ execution } of the communication task can be extended at { TAIL ~ a later time }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL