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