  The inclusion of the continuum in the study of weakly-bound three-body
systems is discussed. A transformed harmonic oscillator basis is introduced to
provide an appropriate discrete and finite basis for treating the continuum
part of the spectrum. As examples of the application of the method the strength
functions corresponding to several operators that couple the ground state to
the continuum are investigated, for 6He, and compared with previous
calculations. It is found that the energy moments of these distributions are
accurately reproduced with a small basis set.
