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