I can prolong you can prolong she can prolong we can prolong you can prolong they can prolong
V-ing form
I can be prolonging you can be prolonging she can be prolonging we can be prolonging you can be prolonging they can be prolonging
Perfect
I can have prolonged you can have prolonged she can have prolonged we can have prolonged you can have prolonged they can have prolonged
V-ing perfect
I can have been prolonging you can have been prolonging she can have been prolonging we can have been prolonging you can have been prolonging they can have been prolonging
Negation
Simple form
I cannot prolong you cannot prolong she cannot prolong we cannot prolong you cannot prolong they cannot prolong
V-ing form
I cannot be prolonging you cannot be prolonging she cannot be prolonging we cannot be prolonging you cannot be prolonging they cannot be prolonging
Perfect
I cannot have prolonged you cannot have prolonged she cannot have prolonged we cannot have prolonged you cannot have prolonged they cannot have prolonged
V-ing perfect
I cannot have been prolonging you cannot have been prolonging she cannot have been prolonging we cannot have been prolonging you cannot have been prolonging they cannot have been prolonging
Interrogative form
Simple form
can I prolong? can you prolong? can she prolong? can we prolong? can you prolong? can they prolong?
V-ing form
can I be prolonging? can you be prolonging? can she be prolonging? can we be prolonging? can you be prolonging? can they be prolonging?
Perfect
can I have prolonged? can you have prolonged? can she have prolonged? can we have prolonged? can you have prolonged? can they have prolonged?
V-ing perfect
can I have been prolonging? can you have been prolonging? can she have been prolonging? can we have been prolonging? can you have been prolonging? can they have been prolonging?
Interro-negative form
Simple form
can I not prolong? can you not prolong? can she not prolong? can we not prolong? can you not prolong? can they not prolong?
V-ing form
can I not be prolonging? can you not be prolonging? can she not be prolonging? can we not be prolonging? can you not be prolonging? can they not be prolonging?
Perfect
can I not have prolonged? can you not have prolonged? can she not have prolonged? can we not have prolonged? can you not have prolonged? can they not have prolonged?
V-ing perfect
can I not have been prolonging? can you not have been prolonging? can she not have been prolonging? can we not have been prolonging? can you not have been prolonging? can they not have been prolonging?