I must learn you must learn she must learn we must learn you must learn they must learn
V-ing form
I must be learning you must be learning she must be learning we must be learning you must be learning they must be learning
Perfect
I must have learned, learnt you must have learned, learnt she must have learned, learnt we must have learned, learnt you must have learned, learnt they must have learned, learnt
V-ing perfect
I must have been learning you must have been learning she must have been learning we must have been learning you must have been learning they must have been learning
Negation
Simple form
I mustn't learn you mustn't learn she mustn't learn we mustn't learn you mustn't learn they mustn't learn
V-ing form
I mustn't be learning you mustn't be learning she mustn't be learning we mustn't be learning you mustn't be learning they mustn't be learning
Perfect
I mustn't have learned, learnt you mustn't have learned, learnt she mustn't have learned, learnt we mustn't have learned, learnt you mustn't have learned, learnt they mustn't have learned, learnt
V-ing perfect
I mustn't have been learning you mustn't have been learning she mustn't have been learning we mustn't have been learning you mustn't have been learning they mustn't have been learning
Interrogative form
Simple form
must I learn? must you learn? must she learn? must we learn? must you learn? must they learn?
V-ing form
must I be learning? must you be learning? must she be learning? must we be learning? must you be learning? must they be learning?
Perfect
must I have learned, learnt? must you have learned, learnt? must she have learned, learnt? must we have learned, learnt? must you have learned, learnt? must they have learned, learnt?
V-ing perfect
must I have been learning? must you have been learning? must she have been learning? must we have been learning? must you have been learning? must they have been learning?
Interro-negative form
Simple form
mustn't I learn? mustn't you learn? mustn't she learn? mustn't we learn? mustn't you learn? mustn't they learn?
V-ing form
mustn't I be learning? mustn't you be learning? mustn't she be learning? mustn't we be learning? mustn't you be learning? mustn't they be learning?
Perfect
mustn't I have learned, learnt? mustn't you have learned, learnt? mustn't she have learned, learnt? mustn't we have learned, learnt? mustn't you have learned, learnt? mustn't they have learned, learnt?
V-ing perfect
mustn't I have been learning? mustn't you have been learning? mustn't she have been learning? mustn't we have been learning? mustn't you have been learning? mustn't they have been learning?