2. In the tetrahedron $S-ABC$, there are three pairs of opposite edges that are equal and are sequentially $2 \sqrt{5}, \sqrt{13}, 2 \sqrt{2}$. Find the volume of the tetrahedron.
$\left(\right.$ Hint: $\because(\sqrt{13})^{2}+(2 \sqrt{2})^{2}>(2$ $\sqrt{5})^{2}, \therefore$ the tetrahedron $S-A B C$ can be completed into a rectangular parallelepiped. It is easy to get $V=\frac{5 \sqrt{30}}{12}$.)