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