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