At the same time, {HEAD ~ the threshold voltage} of {TAIL ~ the P type TFT} is lowered while that of the N type TFT increases 
of
At the same time , { HEAD ~ the threshold voltage } of { TAIL ~ the P type TFT } is lowered while that of the N type TFT increases
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH