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