  Preliminary results of our analysis on the extended emission of short/medium
duration GRBs observed with Swift/BAT are presented. The Bayesian blocks
algorithm is used to analyze the burst durations and the temporal structure of
the lightcurves in different energy bands. We show here the results of three
bursts (GRBs 050724, 061006 and 070714B) that have a prominent soft extended
emission component in our sample. The extended emission of these bursts is a
continuous, flickering-liked component, lasting $\sim 100$ seconds post the GRB
trigger at 15-25 keV bands. Without considering this component, the three
bursts are classified as short GRBs, with $T_{90}=2\sim 3$ seconds. GRB 060614
has an emission component similar to the extended emission, but this component
has pulse-liked structure, possibly indicating that this emission component is
different from that observed in GRBs 050724, 061006, and 070714B. Further
analysis on the spectral evolution behavior of the extended emission component
is on going.
