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