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