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