I can forget you can forget she can forget we can forget you can forget they can forget
V-ing form
I can be forgetting you can be forgetting she can be forgetting we can be forgetting you can be forgetting they can be forgetting
Perfect
I can have forgotten you can have forgotten she can have forgotten we can have forgotten you can have forgotten they can have forgotten
V-ing perfect
I can have been forgetting you can have been forgetting she can have been forgetting we can have been forgetting you can have been forgetting they can have been forgetting
Negation
Simple form
I cannot forget you cannot forget she cannot forget we cannot forget you cannot forget they cannot forget
V-ing form
I cannot be forgetting you cannot be forgetting she cannot be forgetting we cannot be forgetting you cannot be forgetting they cannot be forgetting
Perfect
I cannot have forgotten you cannot have forgotten she cannot have forgotten we cannot have forgotten you cannot have forgotten they cannot have forgotten
V-ing perfect
I cannot have been forgetting you cannot have been forgetting she cannot have been forgetting we cannot have been forgetting you cannot have been forgetting they cannot have been forgetting
Interrogative form
Simple form
can I forget? can you forget? can she forget? can we forget? can you forget? can they forget?
V-ing form
can I be forgetting? can you be forgetting? can she be forgetting? can we be forgetting? can you be forgetting? can they be forgetting?
Perfect
can I have forgotten? can you have forgotten? can she have forgotten? can we have forgotten? can you have forgotten? can they have forgotten?
V-ing perfect
can I have been forgetting? can you have been forgetting? can she have been forgetting? can we have been forgetting? can you have been forgetting? can they have been forgetting?
Interro-negative form
Simple form
can I not forget? can you not forget? can she not forget? can we not forget? can you not forget? can they not forget?
V-ing form
can I not be forgetting? can you not be forgetting? can she not be forgetting? can we not be forgetting? can you not be forgetting? can they not be forgetting?
Perfect
can I not have forgotten? can you not have forgotten? can she not have forgotten? can we not have forgotten? can you not have forgotten? can they not have forgotten?
V-ing perfect
can I not have been forgetting? can you not have been forgetting? can she not have been forgetting? can we not have been forgetting? can you not have been forgetting? can they not have been forgetting?