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