I could pencil you could pencil he could pencil we could pencil you could pencil they could pencil
V-ing form
I could be pencilling you could be pencilling he could be pencilling we could be pencilling you could be pencilling they could be pencilling
Perfect
I could have pencilled you could have pencilled he could have pencilled we could have pencilled you could have pencilled they could have pencilled
V-ing perfect
I could have been pencilling you could have been pencilling he could have been pencilling we could have been pencilling you could have been pencilling they could have been pencilling
Negation
Simple form
I could not pencil you could not pencil he could not pencil we could not pencil you could not pencil they could not pencil
V-ing form
I could not be pencilling you could not be pencilling he could not be pencilling we could not be pencilling you could not be pencilling they could not be pencilling
Perfect
I could not have pencilled you could not have pencilled he could not have pencilled we could not have pencilled you could not have pencilled they could not have pencilled
V-ing perfect
I could not have been pencilling you could not have been pencilling he could not have been pencilling we could not have been pencilling you could not have been pencilling they could not have been pencilling
Interrogative form
Simple form
could I pencil? could you pencil? could he pencil? could we pencil? could you pencil? could they pencil?
V-ing form
could I be pencilling? could you be pencilling? could he be pencilling? could we be pencilling? could you be pencilling? could they be pencilling?
Perfect
could I have pencilled? could you have pencilled? could he have pencilled? could we have pencilled? could you have pencilled? could they have pencilled?
V-ing perfect
could I have been pencilling? could you have been pencilling? could he have been pencilling? could we have been pencilling? could you have been pencilling? could they have been pencilling?
Interro-negative form
Simple form
could I not pencil? could you not pencil? could he not pencil? could we not pencil? could you not pencil? could they not pencil?
V-ing form
could I not be pencilling? could you not be pencilling? could he not be pencilling? could we not be pencilling? could you not be pencilling? could they not be pencilling?
Perfect
could I not have pencilled? could you not have pencilled? could he not have pencilled? could we not have pencilled? could you not have pencilled? could they not have pencilled?
V-ing perfect
could I not have been pencilling? could you not have been pencilling? could he not have been pencilling? could we not have been pencilling? could you not have been pencilling? could they not have been pencilling?