Manipulate[Show[
ContourPlot3D[x==0,{x,-1,5},{y,-1,5},{z,0,5},Mesh->False,PlotRange->{{-0.5,5.5},{-0.5,5.5},{-0.5,5.5}},ImageSize->600,AxesOrigin->{0,0,0},ContourStyle->Opacity[0.9]],
ContourPlot3D[y==0,{x,-1,5},{y,-1,5},{z,0,5},Mesh->False,ContourStyle->Opacity[0.9]],
ContourPlot3D[z==2,{x,-1,5},{y,-1,5},{z,0,5},Mesh->False,ContourStyle->Opacity[0.9]],
ContourPlot3D[x+y+z==4,{x,-1,5},{y,-1,5},{z,0,5},Mesh->False,ContourStyle->Opacity[0.7]],
ParametricPlot3D[{t,2-t,2},{t,0,2},PlotStyle->{Thickness[0.008],Red,Opacity[B]}],
ParametricPlot3D[{0,0,t+2},{t,0,2},PlotStyle->{Thickness[0.008],Red,Opacity[B]}],
ParametricPlot3D[{0,t,2},{t,0,2},PlotStyle->{Thickness[0.008],Red,Opacity[B]}],
ParametricPlot3D[{t,0,2},{t,0,2},PlotStyle->{Thickness[0.008],Red,Opacity[B]}],
ParametricPlot3D[{0,t,4-t},{t,0,2},PlotStyle->{Thickness[0.008],Red,Opacity[B]}],
ParametricPlot3D[{t,0,4-t},{t,0,2},PlotStyle->{Thickness[0.008],Red,Opacity[B]}]
],{{B,0,"Show Edges of Solid"},{0,1}}]

Show[
ContourPlot3D[z==x^2+y^2,{x,-2.5,2.5},{y,-2.5,2.5},{z,0,4.5},Mesh->False,ContourStyle->Opacity[0.7],AxesOrigin->{0,0,0},ImageSize->600],
ContourPlot3D[z==4,{x,-2.5,2.5},{y,-2.5,2.5},{z,0,4.5},Mesh->False,ContourStyle->Opacity[0.7]]
]

Manipulate[Show[
ContourPlot3D[x==0,{x,-0.5,1.5},{y,-0.5,1.5},{z,-0.5,1.5},Mesh->False,PlotRange->{{-0.5,1.5},{-0.5,1.5},{-0.5,1.5}},ImageSize->600,AxesOrigin->{0,0,0},ContourStyle->Opacity[0.9*P],BoundaryStyle->None],
ContourPlot3D[y==0,{x,-0.5,1.5},{y,-0.5,1.5},{z,-0.5,1.5},Mesh->False,ContourStyle->Opacity[0.9*P],BoundaryStyle->None],
ContourPlot3D[z==0,{x,-0.5,1.5},{y,-0.5,1.5},{z,-0.5,1.5},Mesh->False,ContourStyle->Opacity[0.9*P],BoundaryStyle->None],
ContourPlot3D[y==1-x,{x,-0.5,1.5},{y,-0.5,1.5},{z,-0.5,1.5},Mesh->False,ContourStyle->Opacity[0.5*P],BoundaryStyle->None],
ContourPlot3D[z==1-x^2,{x,-0.5,1.5},{y,-0.5,1.5},{z,-0.5,1.5},Mesh->False,ContourStyle->Opacity[0.7*P],BoundaryStyle->None],
ParametricPlot3D[{0,0,t},{t,0,1},PlotStyle->{Thickness[0.008],Red,Opacity[B]}],
ParametricPlot3D[{0,t,0},{t,0,1},PlotStyle->{Thickness[0.008],Red,Opacity[B]}],
ParametricPlot3D[{t,0,0},{t,0,1},PlotStyle->{Thickness[0.008],Red,Opacity[B]}],
ParametricPlot3D[{0,t,1},{t,0,1},PlotStyle->{Thickness[0.008],Red,Opacity[B]}],
ParametricPlot3D[{0,1,t},{t,0,1},PlotStyle->{Thickness[0.008],Red,Opacity[B]}],
ParametricPlot3D[{t,0,1-t^2},{t,0,1},PlotStyle->{Thickness[0.008],Red,Opacity[B]}],
ParametricPlot3D[{t,1-t,1-t^2},{t,0,1},PlotStyle->{Thickness[0.008],Red,Opacity[B]}],
ParametricPlot3D[{t,1-t,0},{t,0,1},PlotStyle->{Thickness[0.008],Red,Opacity[B]}]
],{{P,1,"Opacity of Boundary Surfaces"},{0,0.5,1}},{{B,0,"Show Edges of Solid"},{0,1}}]