Q:

Three plots in two rows aligned at center

I wrote this code:   
UT := 1 + x^2 
VT := t*x^2
WT := t
    Show[GraphicsGrid[{{Plot3D[UT, {x, 0, 1}, {t, 0, 0.8}], 
        Plot3D[VT, {x, 0, 1}, {t, 0, 0.8}], 
        Plot3D[WT, {x, 0, 1}, {t, 0, 0.8}]}}], ImageSize -> Large]

I want to export the following, with the third plot centered in the row:

Any suggestion?

A:

Probably you want the following:
UT := 1 + x^2
VT := t*x^2
WT := t
Column[{Row[{Plot3D[UT, {x, 0, 1}, {t, 0, 0.8}], Plot3D[VT, {x, 0, 1}, {t, 0, 0.8}]}], 
  Plot3D[WT, {x, 0, 1}, {t, 0, 0.8}]}, Center, BaseStyle -> ImageSizeMultipliers -> 1]

