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