For example, if {HEAD ~ a user} is on {TAIL ~ a voice call} using a cellular telephone, the cell phone might not be equipped to handle video content 
For example , if { HEAD ~ a user } is on { TAIL ~ a voice call } using a cellular telephone , the cell phone might not be equipped to handle video content
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH