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