Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I must ski ski you must ski ski he must ski ski we must ski ski you must ski ski they must ski ski
V-ing form
I must be ski skiing you must be ski skiing he must be ski skiing we must be ski skiing you must be ski skiing they must be ski skiing
Perfect
I must have ski skied you must have ski skied he must have ski skied we must have ski skied you must have ski skied they must have ski skied
V-ing perfect
I must have been ski skiing you must have been ski skiing he must have been ski skiing we must have been ski skiing you must have been ski skiing they must have been ski skiing
Negation
Simple form
I mustn't ski ski you mustn't ski ski he mustn't ski ski we mustn't ski ski you mustn't ski ski they mustn't ski ski
V-ing form
I mustn't be ski skiing you mustn't be ski skiing he mustn't be ski skiing we mustn't be ski skiing you mustn't be ski skiing they mustn't be ski skiing
Perfect
I mustn't have ski skied you mustn't have ski skied he mustn't have ski skied we mustn't have ski skied you mustn't have ski skied they mustn't have ski skied
V-ing perfect
I mustn't have been ski skiing you mustn't have been ski skiing he mustn't have been ski skiing we mustn't have been ski skiing you mustn't have been ski skiing they mustn't have been ski skiing
Interrogative form
Simple form
must I ski ski? must you ski ski? must he ski ski? must we ski ski? must you ski ski? must they ski ski?
V-ing form
must I be ski skiing? must you be ski skiing? must he be ski skiing? must we be ski skiing? must you be ski skiing? must they be ski skiing?
Perfect
must I have ski skied? must you have ski skied? must he have ski skied? must we have ski skied? must you have ski skied? must they have ski skied?
V-ing perfect
must I have been ski skiing? must you have been ski skiing? must he have been ski skiing? must we have been ski skiing? must you have been ski skiing? must they have been ski skiing?
Interro-negative form
Simple form
mustn't I ski ski? mustn't you ski ski? mustn't he ski ski? mustn't we ski ski? mustn't you ski ski? mustn't they ski ski?
V-ing form
mustn't I be ski skiing? mustn't you be ski skiing? mustn't he be ski skiing? mustn't we be ski skiing? mustn't you be ski skiing? mustn't they be ski skiing?
Perfect
mustn't I have ski skied? mustn't you have ski skied? mustn't he have ski skied? mustn't we have ski skied? mustn't you have ski skied? mustn't they have ski skied?
V-ing perfect
mustn't I have been ski skiing? mustn't you have been ski skiing? mustn't he have been ski skiing? mustn't we have been ski skiing? mustn't you have been ski skiing? mustn't they have been ski skiing?