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