  In the neutron-deuteron scattering, four total cross sections are shown to
form a complete set for the determination of the imaginary parts of the forward
amplitudes because of the optical theorem. The amplitudes are decomposed into
scalar and tensor ones in the spin space. Contributions of three-nucleon forces
(3NF) to these amplitudes are studied, by the Faddeev calculation, which
predicts significant tensor effects of the 3NF.
