I could produce you could produce she could produce we could produce you could produce they could produce
V-ing form
I could be producing you could be producing she could be producing we could be producing you could be producing they could be producing
Perfect
I could have produced you could have produced she could have produced we could have produced you could have produced they could have produced
V-ing perfect
I could have been producing you could have been producing she could have been producing we could have been producing you could have been producing they could have been producing
Negation
Simple form
I couldn't produce you couldn't produce she couldn't produce we couldn't produce you couldn't produce they couldn't produce
V-ing form
I couldn't be producing you couldn't be producing she couldn't be producing we couldn't be producing you couldn't be producing they couldn't be producing
Perfect
I couldn't have produced you couldn't have produced she couldn't have produced we couldn't have produced you couldn't have produced they couldn't have produced
V-ing perfect
I couldn't have been producing you couldn't have been producing she couldn't have been producing we couldn't have been producing you couldn't have been producing they couldn't have been producing
Interrogative form
Simple form
could I produce? could you produce? could she produce? could we produce? could you produce? could they produce?
V-ing form
could I be producing? could you be producing? could she be producing? could we be producing? could you be producing? could they be producing?
Perfect
could I have produced? could you have produced? could she have produced? could we have produced? could you have produced? could they have produced?
V-ing perfect
could I have been producing? could you have been producing? could she have been producing? could we have been producing? could you have been producing? could they have been producing?
Interro-negative form
Simple form
couldn't I produce? couldn't you produce? couldn't she produce? couldn't we produce? couldn't you produce? couldn't they produce?
V-ing form
couldn't I be producing? couldn't you be producing? couldn't she be producing? couldn't we be producing? couldn't you be producing? couldn't they be producing?
Perfect
couldn't I have produced? couldn't you have produced? couldn't she have produced? couldn't we have produced? couldn't you have produced? couldn't they have produced?
V-ing perfect
couldn't I have been producing? couldn't you have been producing? couldn't she have been producing? couldn't we have been producing? couldn't you have been producing? couldn't they have been producing?