  The phase-sensitive experiments on cuprate superconductors have told us about
the symmetry of the condensate wavefunction. However, they can not determine
the pairing symmetry of Cooper pairs. To describe a superconducting state, two
wavefunctions are needed, condensate wavefunction and pairing wavefunction. The
former describes the entirety movement of the pairs and the latter describes
the relative movement of the two electrons within a pair. The $\pi$-phase shift
observed in the phase sensitive Josephson measurements can not prove that the
pairing state is d-wave. We present here a new explanation and predict some new
observable phenomena.
