  In this paper, we calculate $RO(C_2)$-graded cohomology of $C_2$-equivariant
Eilenberg-Mac Lane spaces $K(\underline{Z/2}, n+\sigma)$ for $n\geq 0$. These
can be used to give the relation between equivariant lambda algebra and
equivariant Adams resolution and equivariant unstable Adams spectral sequence,
which are defined in author`s dissertation.
