I must discolour you must discolour she must discolour we must discolour you must discolour they must discolour
V-ing form
I must be discolouring you must be discolouring she must be discolouring we must be discolouring you must be discolouring they must be discolouring
Perfect
I must have discoloured you must have discoloured she must have discoloured we must have discoloured you must have discoloured they must have discoloured
V-ing perfect
I must have been discolouring you must have been discolouring she must have been discolouring we must have been discolouring you must have been discolouring they must have been discolouring
Negation
Simple form
I must not discolour you must not discolour she must not discolour we must not discolour you must not discolour they must not discolour
V-ing form
I must not be discolouring you must not be discolouring she must not be discolouring we must not be discolouring you must not be discolouring they must not be discolouring
Perfect
I must not have discoloured you must not have discoloured she must not have discoloured we must not have discoloured you must not have discoloured they must not have discoloured
V-ing perfect
I must not have been discolouring you must not have been discolouring she must not have been discolouring we must not have been discolouring you must not have been discolouring they must not have been discolouring
Interrogative form
Simple form
must I discolour? must you discolour? must she discolour? must we discolour? must you discolour? must they discolour?
V-ing form
must I be discolouring? must you be discolouring? must she be discolouring? must we be discolouring? must you be discolouring? must they be discolouring?
Perfect
must I have discoloured? must you have discoloured? must she have discoloured? must we have discoloured? must you have discoloured? must they have discoloured?
V-ing perfect
must I have been discolouring? must you have been discolouring? must she have been discolouring? must we have been discolouring? must you have been discolouring? must they have been discolouring?
Interro-negative form
Simple form
must I not discolour? must you not discolour? must she not discolour? must we not discolour? must you not discolour? must they not discolour?
V-ing form
must I not be discolouring? must you not be discolouring? must she not be discolouring? must we not be discolouring? must you not be discolouring? must they not be discolouring?
Perfect
must I not have discoloured? must you not have discoloured? must she not have discoloured? must we not have discoloured? must you not have discoloured? must they not have discoloured?
V-ing perfect
must I not have been discolouring? must you not have been discolouring? must she not have been discolouring? must we not have been discolouring? must you not have been discolouring? must they not have been discolouring?