I could even you could even she could even we could even you could even they could even
V-ing form
I could be evening you could be evening she could be evening we could be evening you could be evening they could be evening
Perfect
I could have evened you could have evened she 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 she could have been evening we could have been evening you could have been evening they could have been evening
Negation
Simple form
I could not even you could not even she could not even we could not even you could not even they could not even
V-ing form
I could not be evening you could not be evening she could not be evening we could not be evening you could not be evening they could not be evening
Perfect
I could not have evened you could not have evened she could not have evened we could not have evened you could not have evened they could not have evened
V-ing perfect
I could not have been evening you could not have been evening she could not have been evening we could not have been evening you could not have been evening they could not have been evening
Interrogative form
Simple form
could I even? could you even? could she even? could we even? could you even? could they even?
V-ing form
could I be evening? could you be evening? could she be evening? could we be evening? could you be evening? could they be evening?
Perfect
could I have evened? could you have evened? could she 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 she have been evening? could we have been evening? could you have been evening? could they have been evening?
Interro-negative form
Simple form
could I not even? could you not even? could she not even? could we not even? could you not even? could they not even?
V-ing form
could I not be evening? could you not be evening? could she not be evening? could we not be evening? could you not be evening? could they not be evening?
Perfect
could I not have evened? could you not have evened? could she not have evened? could we not have evened? could you not have evened? could they not have evened?
V-ing perfect
could I not have been evening? could you not have been evening? could she not have been evening? could we not have been evening? could you not have been evening? could they not have been evening?