  By using generalized vertex algebras associated to rational lattices, we
construct explicitly the admissible modules for the affine Lie algebra $A_1
^{(1)}$ of level $-{4/3}$. As an application, we show that the W(2,5) algebra
with central charge c=-7 investigated in math.QA/0207155 is a subalgebra of the
simple affine vertex operator algebra $L(-{4/3}\Lambda_0)$.
