I could shade you could shade he could shade we could shade you could shade they could shade
V-ing form
I could be shading you could be shading he could be shading we could be shading you could be shading they could be shading
Perfect
I could have shaded you could have shaded he could have shaded we could have shaded you could have shaded they could have shaded
V-ing perfect
I could have been shading you could have been shading he could have been shading we could have been shading you could have been shading they could have been shading
Negation
Simple form
I couldn't shade you couldn't shade he couldn't shade we couldn't shade you couldn't shade they couldn't shade
V-ing form
I couldn't be shading you couldn't be shading he couldn't be shading we couldn't be shading you couldn't be shading they couldn't be shading
Perfect
I couldn't have shaded you couldn't have shaded he couldn't have shaded we couldn't have shaded you couldn't have shaded they couldn't have shaded
V-ing perfect
I couldn't have been shading you couldn't have been shading he couldn't have been shading we couldn't have been shading you couldn't have been shading they couldn't have been shading
Interrogative form
Simple form
could I shade? could you shade? could he shade? could we shade? could you shade? could they shade?
V-ing form
could I be shading? could you be shading? could he be shading? could we be shading? could you be shading? could they be shading?
Perfect
could I have shaded? could you have shaded? could he have shaded? could we have shaded? could you have shaded? could they have shaded?
V-ing perfect
could I have been shading? could you have been shading? could he have been shading? could we have been shading? could you have been shading? could they have been shading?
Interro-negative form
Simple form
couldn't I shade? couldn't you shade? couldn't he shade? couldn't we shade? couldn't you shade? couldn't they shade?
V-ing form
couldn't I be shading? couldn't you be shading? couldn't he be shading? couldn't we be shading? couldn't you be shading? couldn't they be shading?
Perfect
couldn't I have shaded? couldn't you have shaded? couldn't he have shaded? couldn't we have shaded? couldn't you have shaded? couldn't they have shaded?
V-ing perfect
couldn't I have been shading? couldn't you have been shading? couldn't he have been shading? couldn't we have been shading? couldn't you have been shading? couldn't they have been shading?