Thus, {HEAD ~ one aspect} of the invention is {TAIL ~ a portable device} having a main unit and a keyboard unit 
is
Thus , { HEAD ~ one aspect } of the invention is { TAIL ~ a portable device } having a main unit and a keyboard unit
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH