  Motivated by experiments on Cs$_2$CuCl$_4$ samples, we studied and classified
the symmetric spin liquids on triangular lattice. We identified 63 $Z_2$ spin
liquids, 30 U(1) spin liquids and 2 SU(2) spin liquids. All those spin liquids
have the same symmetry but different quantum orders. We calculated the spin
spectral functions in some simple spin liquids and compared them to the one
measured by experiments on Cs$_2$CuCl$_4$. We find that the $U1C\tau
_{+}^0\tau_{-}^0\tau^1$ spin liquid or one of its relatives is consistent with
observed properties of the spin liquid state in Cs$_2$CuCl$_4$. We discussed
the fine distinctions among those possible spin liquids and the spin liquids
proposed using slave-fermion approach, so that future experiments can determine
which spin liquids actually describe the spin state in Cs$_2$CuCl$_4$.
