  Angular and energy distributions for leptons and bottom quarks in the process
e+e- --> t tbar --> l/b ... have been calculated assuming the most general
top-quark couplings. The double distributions depend both on modification of
the top-quark production and tbW decay vertices. However, the leptonic angular
distribution turned out to be insensitive to non-standard parts of tbW vertex.
The method of optimal observables have been used to estimate sensitivity of
future measurements at linear e+e- colliders
