  The action of supersymmetric Born-Infeld theory (D-9-brane in a Lorentz
covariant static gauge) has a geometric form of the Volkov-Akulov-type. The
first non-linearly realized supersymmetry can be made manifest, the second
world-volume supersymmetry is not manifest. We also study the analogous 2
supersymmetries of the quadratic action of the covariantly quantized D-0-brane.
We show that the Hamiltonian and the BRST operator are build from these two
supersymmetry generators.
