I could bog you could bog he could bog we could bog you could bog they could bog
V-ing form
I could be bogging you could be bogging he could be bogging we could be bogging you could be bogging they could be bogging
Perfect
I could have bogged you could have bogged he could have bogged we could have bogged you could have bogged they could have bogged
V-ing perfect
I could have been bogging you could have been bogging he could have been bogging we could have been bogging you could have been bogging they could have been bogging
Negation
Simple form
I couldn't bog you couldn't bog he couldn't bog we couldn't bog you couldn't bog they couldn't bog
V-ing form
I couldn't be bogging you couldn't be bogging he couldn't be bogging we couldn't be bogging you couldn't be bogging they couldn't be bogging
Perfect
I couldn't have bogged you couldn't have bogged he couldn't have bogged we couldn't have bogged you couldn't have bogged they couldn't have bogged
V-ing perfect
I couldn't have been bogging you couldn't have been bogging he couldn't have been bogging we couldn't have been bogging you couldn't have been bogging they couldn't have been bogging
Interrogative form
Simple form
could I bog? could you bog? could he bog? could we bog? could you bog? could they bog?
V-ing form
could I be bogging? could you be bogging? could he be bogging? could we be bogging? could you be bogging? could they be bogging?
Perfect
could I have bogged? could you have bogged? could he have bogged? could we have bogged? could you have bogged? could they have bogged?
V-ing perfect
could I have been bogging? could you have been bogging? could he have been bogging? could we have been bogging? could you have been bogging? could they have been bogging?
Interro-negative form
Simple form
couldn't I bog? couldn't you bog? couldn't he bog? couldn't we bog? couldn't you bog? couldn't they bog?
V-ing form
couldn't I be bogging? couldn't you be bogging? couldn't he be bogging? couldn't we be bogging? couldn't you be bogging? couldn't they be bogging?
Perfect
couldn't I have bogged? couldn't you have bogged? couldn't he have bogged? couldn't we have bogged? couldn't you have bogged? couldn't they have bogged?
V-ing perfect
couldn't I have been bogging? couldn't you have been bogging? couldn't he have been bogging? couldn't we have been bogging? couldn't you have been bogging? couldn't they have been bogging?