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