English verb conjugation
COULD PROLONG

Regular verb: prolong - prolonged - prolonged

Affirmation

Simple form	V-ing form
I could prolong you could prolong she could prolong we could prolong you could prolong they could prolong	I could be prolonging you could be prolonging she could be prolonging we could be prolonging you could be prolonging they could be prolonging
Perfect	V-ing perfect
I could have prolonged you could have prolonged she could have prolonged we could have prolonged you could have prolonged they could have prolonged	I could have been prolonging you could have been prolonging she could have been prolonging we could have been prolonging you could have been prolonging they could have been prolonging

Negation

Simple form	V-ing form
I couldn't prolong you couldn't prolong she couldn't prolong we couldn't prolong you couldn't prolong they couldn't prolong	I couldn't be prolonging you couldn't be prolonging she couldn't be prolonging we couldn't be prolonging you couldn't be prolonging they couldn't be prolonging
Perfect	V-ing perfect
I couldn't have prolonged you couldn't have prolonged she couldn't have prolonged we couldn't have prolonged you couldn't have prolonged they couldn't have prolonged	I couldn't have been prolonging you couldn't have been prolonging she couldn't have been prolonging we couldn't have been prolonging you couldn't have been prolonging they couldn't have been prolonging

Interrogative form

Simple form	V-ing form
could I prolong? could you prolong? could she prolong? could we prolong? could you prolong? could they prolong?	could I be prolonging? could you be prolonging? could she be prolonging? could we be prolonging? could you be prolonging? could they be prolonging?
Perfect	V-ing perfect
could I have prolonged? could you have prolonged? could she have prolonged? could we have prolonged? could you have prolonged? could they have prolonged?	could I have been prolonging? could you have been prolonging? could she have been prolonging? could we have been prolonging? could you have been prolonging? could they have been prolonging?

Interro-negative form

Simple form	V-ing form
couldn't I prolong? couldn't you prolong? couldn't she prolong? couldn't we prolong? couldn't you prolong? couldn't they prolong?	couldn't I be prolonging? couldn't you be prolonging? couldn't she be prolonging? couldn't we be prolonging? couldn't you be prolonging? couldn't they be prolonging?
Perfect	V-ing perfect
couldn't I have prolonged? couldn't you have prolonged? couldn't she have prolonged? couldn't we have prolonged? couldn't you have prolonged? couldn't they have prolonged?	couldn't I have been prolonging? couldn't you have been prolonging? couldn't she have been prolonging? couldn't we have been prolonging? couldn't you have been prolonging? couldn't they have been prolonging?