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