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