I must skipper you must skipper she must skipper we must skipper you must skipper they must skipper
V-ing form
I must be skippering you must be skippering she must be skippering we must be skippering you must be skippering they must be skippering
Perfect
I must have skippered you must have skippered she must have skippered we must have skippered you must have skippered they must have skippered
V-ing perfect
I must have been skippering you must have been skippering she must have been skippering we must have been skippering you must have been skippering they must have been skippering
Negation
Simple form
I must not skipper you must not skipper she must not skipper we must not skipper you must not skipper they must not skipper
V-ing form
I must not be skippering you must not be skippering she must not be skippering we must not be skippering you must not be skippering they must not be skippering
Perfect
I must not have skippered you must not have skippered she must not have skippered we must not have skippered you must not have skippered they must not have skippered
V-ing perfect
I must not have been skippering you must not have been skippering she must not have been skippering we must not have been skippering you must not have been skippering they must not have been skippering
Interrogative form
Simple form
must I skipper? must you skipper? must she skipper? must we skipper? must you skipper? must they skipper?
V-ing form
must I be skippering? must you be skippering? must she be skippering? must we be skippering? must you be skippering? must they be skippering?
Perfect
must I have skippered? must you have skippered? must she have skippered? must we have skippered? must you have skippered? must they have skippered?
V-ing perfect
must I have been skippering? must you have been skippering? must she have been skippering? must we have been skippering? must you have been skippering? must they have been skippering?
Interro-negative form
Simple form
must I not skipper? must you not skipper? must she not skipper? must we not skipper? must you not skipper? must they not skipper?
V-ing form
must I not be skippering? must you not be skippering? must she not be skippering? must we not be skippering? must you not be skippering? must they not be skippering?
Perfect
must I not have skippered? must you not have skippered? must she not have skippered? must we not have skippered? must you not have skippered? must they not have skippered?
V-ing perfect
must I not have been skippering? must you not have been skippering? must she not have been skippering? must we not have been skippering? must you not have been skippering? must they not have been skippering?