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