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