Smooth structures on Σ×R

We prove that there are uncountably many smooth structures on the four manifold Σ×R if Σ belongs to one of the following classes: 1. al homology spheres; t 3-manifolds; flat 3-manifolds. er, when Σ is a rational homology sphere, these smooth structures on Σ×R can be embedded into the connected sums of CP2.