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