I can refine you can refine she can refine we can refine you can refine they can refine
V-ing form
I can be refining you can be refining she can be refining we can be refining you can be refining they can be refining
Perfect
I can have refined you can have refined she can have refined we can have refined you can have refined they can have refined
V-ing perfect
I can have been refining you can have been refining she can have been refining we can have been refining you can have been refining they can have been refining
Negation
Simple form
I can't refine you can't refine she can't refine we can't refine you can't refine they can't refine
V-ing form
I can't be refining you can't be refining she can't be refining we can't be refining you can't be refining they can't be refining
Perfect
I can't have refined you can't have refined she can't have refined we can't have refined you can't have refined they can't have refined
V-ing perfect
I can't have been refining you can't have been refining she can't have been refining we can't have been refining you can't have been refining they can't have been refining
Interrogative form
Simple form
can I refine? can you refine? can she refine? can we refine? can you refine? can they refine?
V-ing form
can I be refining? can you be refining? can she be refining? can we be refining? can you be refining? can they be refining?
Perfect
can I have refined? can you have refined? can she have refined? can we have refined? can you have refined? can they have refined?
V-ing perfect
can I have been refining? can you have been refining? can she have been refining? can we have been refining? can you have been refining? can they have been refining?
Interro-negative form
Simple form
can't I refine? can't you refine? can't she refine? can't we refine? can't you refine? can't they refine?
V-ing form
can't I be refining? can't you be refining? can't she be refining? can't we be refining? can't you be refining? can't they be refining?
Perfect
can't I have refined? can't you have refined? can't she have refined? can't we have refined? can't you have refined? can't they have refined?
V-ing perfect
can't I have been refining? can't you have been refining? can't she have been refining? can't we have been refining? can't you have been refining? can't they have been refining?