Example 17 (1999 Henan Province Competition Question) In the tetrahedron $S-ABC$, the three pairs of opposite edges are equal, being $\sqrt{34}$, $\sqrt{41}$, and $5$ respectively. Then the volume of this tetrahedron is ( ).
A. 20
B. $10 \sqrt{7}$
C. $20 \sqrt{3}$
D. 30
Solution: Choose A. Reason: As shown in Figure 5-17, complete the rectangular prism, and let its length, width, and height be $x$, $y$, and $z$, respectively. Then we have
$$
\left\{\begin{array}{l}
x^{2}+y^{2}=5^{2}, \\
y^{2}+z^{2}=(\sqrt{41})^{2}, \\
z^{2}+x^{2}=(\sqrt{34})^{2} .
\end{array}\right.
$$

Solving these equations yields $x=3, y=4, z=5$.
Thus, $V_{\text {S-ABC }}=\frac{1}{3} V_{\text {rectangular prism}}=\frac{1}{3} \times 3 \times 4 \times 5=20$.