  The end-point singularity is an unsolved problem in BBNS approach.
Incorporating the partonic transverse momentum and the Sudakov form factor,
this problem can be solved model-independently. We discuss the Sudakov effects
in BBNS approach. The BBNS approach is compared with the modified PQCD
approach. The main idea of Sudakov form factor is briefly discussed. Our
conclusion is that the twist-3 contribution for the hard spectator scattering
is numerically not important in $B\to \pi\pi$ decays, compared with the twist-2
contribution.
