8. Let the 20 vertices of a regular 20-sided polygon inscribed in the unit circle in the complex plane correspond to the complex numbers $z_{1}, z_{2}, \cdots, z_{20}$, respectively. Then, how many different points do the complex numbers $z_{1}^{1995}, z_{2}^{1995}, \cdots, z_{20}^{1995}$ correspond to?
8. Let $z_{1}=\cos \theta+i \sin \theta$, then $z_{k}=(\cos \theta+i \sin \theta)\left[\cos \frac{2 k \pi-2 \pi}{20}+i \sin \frac{2 k \pi-2 \pi}{20}\right]$ $(k=1,2, \cdots, 20)$. Therefore, $z_{k}^{1995}=(\cos 1995 \theta+i \sin 1995 \theta)(-i)^{k-1}(k=1,2, \cdots, 20)$, from which we can see that there are four different values.