I could refrain you could refrain she could refrain we could refrain you could refrain they could refrain
V-ing form
I could be refraining you could be refraining she could be refraining we could be refraining you could be refraining they could be refraining
Perfect
I could have refrained you could have refrained she could have refrained we could have refrained you could have refrained they could have refrained
V-ing perfect
I could have been refraining you could have been refraining she could have been refraining we could have been refraining you could have been refraining they could have been refraining
Negation
Simple form
I could not refrain you could not refrain she could not refrain we could not refrain you could not refrain they could not refrain
V-ing form
I could not be refraining you could not be refraining she could not be refraining we could not be refraining you could not be refraining they could not be refraining
Perfect
I could not have refrained you could not have refrained she could not have refrained we could not have refrained you could not have refrained they could not have refrained
V-ing perfect
I could not have been refraining you could not have been refraining she could not have been refraining we could not have been refraining you could not have been refraining they could not have been refraining
Interrogative form
Simple form
could I refrain? could you refrain? could she refrain? could we refrain? could you refrain? could they refrain?
V-ing form
could I be refraining? could you be refraining? could she be refraining? could we be refraining? could you be refraining? could they be refraining?
Perfect
could I have refrained? could you have refrained? could she have refrained? could we have refrained? could you have refrained? could they have refrained?
V-ing perfect
could I have been refraining? could you have been refraining? could she have been refraining? could we have been refraining? could you have been refraining? could they have been refraining?
Interro-negative form
Simple form
could I not refrain? could you not refrain? could she not refrain? could we not refrain? could you not refrain? could they not refrain?
V-ing form
could I not be refraining? could you not be refraining? could she not be refraining? could we not be refraining? could you not be refraining? could they not be refraining?
Perfect
could I not have refrained? could you not have refrained? could she not have refrained? could we not have refrained? could you not have refrained? could they not have refrained?
V-ing perfect
could I not have been refraining? could you not have been refraining? could she not have been refraining? could we not have been refraining? could you not have been refraining? could they not have been refraining?