I could disagree you could disagree she could disagree we could disagree you could disagree they could disagree
V-ing form
I could be disagreeing you could be disagreeing she could be disagreeing we could be disagreeing you could be disagreeing they could be disagreeing
Perfect
I could have disagreed you could have disagreed she 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 she 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 she 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 she 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 she 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 she 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 she disagree? could we disagree? could you disagree? could they disagree?
V-ing form
could I be disagreeing? could you be disagreeing? could she be disagreeing? could we be disagreeing? could you be disagreeing? could they be disagreeing?
Perfect
could I have disagreed? could you have disagreed? could she 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 she 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 she 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 she 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 she 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 she have been disagreeing? couldn't we have been disagreeing? couldn't you have been disagreeing? couldn't they have been disagreeing?