  The high-spin rotational properties of two-quasiparticle bands in the
doubly-odd ${}^{166}$Ta are analyzed using the cranked shell model with pairing
correlations treated by a particle-number conserving method, in which the
blocking effects are taken into account exactly. The experimental moments of
inertia and alignments and their variations with the rotational frequency
$\hbar\omega$ are reproduced very well by the particle-number conserving
calculations, which provides a reliable support to the configuration
assignments in previous works for these bands. The backbendings in these
two-quasiparticle bands are analyzed by the calculated occupation probabilities
and the contributions of each orbital to the total angular momentum alignments.
The moments of inertia and alignments for the Gallagher-Moszkowski partners of
these observed two-quasiparticle rotational bands are also predicted.
