I could sow you could sow he could sow we could sow you could sow they could sow
V-ing form
I could be sowing you could be sowing he could be sowing we could be sowing you could be sowing they could be sowing
Perfect
I could have sown, sowed you could have sown, sowed he could have sown, sowed we could have sown, sowed you could have sown, sowed they could have sown, sowed
V-ing perfect
I could have been sowing you could have been sowing he could have been sowing we could have been sowing you could have been sowing they could have been sowing
Negation
Simple form
I couldn't sow you couldn't sow he couldn't sow we couldn't sow you couldn't sow they couldn't sow
V-ing form
I couldn't be sowing you couldn't be sowing he couldn't be sowing we couldn't be sowing you couldn't be sowing they couldn't be sowing
Perfect
I couldn't have sown, sowed you couldn't have sown, sowed he couldn't have sown, sowed we couldn't have sown, sowed you couldn't have sown, sowed they couldn't have sown, sowed
V-ing perfect
I couldn't have been sowing you couldn't have been sowing he couldn't have been sowing we couldn't have been sowing you couldn't have been sowing they couldn't have been sowing
Interrogative form
Simple form
could I sow? could you sow? could he sow? could we sow? could you sow? could they sow?
V-ing form
could I be sowing? could you be sowing? could he be sowing? could we be sowing? could you be sowing? could they be sowing?
Perfect
could I have sown, sowed? could you have sown, sowed? could he have sown, sowed? could we have sown, sowed? could you have sown, sowed? could they have sown, sowed?
V-ing perfect
could I have been sowing? could you have been sowing? could he have been sowing? could we have been sowing? could you have been sowing? could they have been sowing?
Interro-negative form
Simple form
couldn't I sow? couldn't you sow? couldn't he sow? couldn't we sow? couldn't you sow? couldn't they sow?
V-ing form
couldn't I be sowing? couldn't you be sowing? couldn't he be sowing? couldn't we be sowing? couldn't you be sowing? couldn't they be sowing?
Perfect
couldn't I have sown, sowed? couldn't you have sown, sowed? couldn't he have sown, sowed? couldn't we have sown, sowed? couldn't you have sown, sowed? couldn't they have sown, sowed?
V-ing perfect
couldn't I have been sowing? couldn't you have been sowing? couldn't he have been sowing? couldn't we have been sowing? couldn't you have been sowing? couldn't they have been sowing?