  For the inverse linear potential, the SO(1,1) field behaves as phantom for
late time and the Big Rip will occur. The field approaches zero as time
approaches the Big Rip, here. For this potential the phantom equation of state
takes the late-time minimum $w_\Phi=-3$. We give some discussions that the Big
Rip in the SO(1,1) model may be treated as either the transition point of
universe from expansion to extract phase or the final state. In the latter
picture of the universe, the field has the $T$ symmetry and the scale factor
possesses the $CT$ symmetry, for which the SO(1,1) charge $\bar{Q}$ plays a
crucial role.
