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