I could couple you could couple she could couple we could couple you could couple they could couple
V-ing form
I could be coupling you could be coupling she could be coupling we could be coupling you could be coupling they could be coupling
Perfect
I could have coupled you could have coupled she could have coupled we could have coupled you could have coupled they could have coupled
V-ing perfect
I could have been coupling you could have been coupling she could have been coupling we could have been coupling you could have been coupling they could have been coupling
Negation
Simple form
I could not couple you could not couple she could not couple we could not couple you could not couple they could not couple
V-ing form
I could not be coupling you could not be coupling she could not be coupling we could not be coupling you could not be coupling they could not be coupling
Perfect
I could not have coupled you could not have coupled she could not have coupled we could not have coupled you could not have coupled they could not have coupled
V-ing perfect
I could not have been coupling you could not have been coupling she could not have been coupling we could not have been coupling you could not have been coupling they could not have been coupling
Interrogative form
Simple form
could I couple? could you couple? could she couple? could we couple? could you couple? could they couple?
V-ing form
could I be coupling? could you be coupling? could she be coupling? could we be coupling? could you be coupling? could they be coupling?
Perfect
could I have coupled? could you have coupled? could she have coupled? could we have coupled? could you have coupled? could they have coupled?
V-ing perfect
could I have been coupling? could you have been coupling? could she have been coupling? could we have been coupling? could you have been coupling? could they have been coupling?
Interro-negative form
Simple form
could I not couple? could you not couple? could she not couple? could we not couple? could you not couple? could they not couple?
V-ing form
could I not be coupling? could you not be coupling? could she not be coupling? could we not be coupling? could you not be coupling? could they not be coupling?
Perfect
could I not have coupled? could you not have coupled? could she not have coupled? could we not have coupled? could you not have coupled? could they not have coupled?
V-ing perfect
could I not have been coupling? could you not have been coupling? could she not have been coupling? could we not have been coupling? could you not have been coupling? could they not have been coupling?