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