I must alternate you must alternate he must alternate we must alternate you must alternate they must alternate
V-ing form
I must be alternating you must be alternating he must be alternating we must be alternating you must be alternating they must be alternating
Perfect
I must have alternated you must have alternated he must have alternated we must have alternated you must have alternated they must have alternated
V-ing perfect
I must have been alternating you must have been alternating he must have been alternating we must have been alternating you must have been alternating they must have been alternating
Negation
Simple form
I mustn't alternate you mustn't alternate he mustn't alternate we mustn't alternate you mustn't alternate they mustn't alternate
V-ing form
I mustn't be alternating you mustn't be alternating he mustn't be alternating we mustn't be alternating you mustn't be alternating they mustn't be alternating
Perfect
I mustn't have alternated you mustn't have alternated he mustn't have alternated we mustn't have alternated you mustn't have alternated they mustn't have alternated
V-ing perfect
I mustn't have been alternating you mustn't have been alternating he mustn't have been alternating we mustn't have been alternating you mustn't have been alternating they mustn't have been alternating
Interrogative form
Simple form
must I alternate? must you alternate? must he alternate? must we alternate? must you alternate? must they alternate?
V-ing form
must I be alternating? must you be alternating? must he be alternating? must we be alternating? must you be alternating? must they be alternating?
Perfect
must I have alternated? must you have alternated? must he have alternated? must we have alternated? must you have alternated? must they have alternated?
V-ing perfect
must I have been alternating? must you have been alternating? must he have been alternating? must we have been alternating? must you have been alternating? must they have been alternating?
Interro-negative form
Simple form
mustn't I alternate? mustn't you alternate? mustn't he alternate? mustn't we alternate? mustn't you alternate? mustn't they alternate?
V-ing form
mustn't I be alternating? mustn't you be alternating? mustn't he be alternating? mustn't we be alternating? mustn't you be alternating? mustn't they be alternating?
Perfect
mustn't I have alternated? mustn't you have alternated? mustn't he have alternated? mustn't we have alternated? mustn't you have alternated? mustn't they have alternated?
V-ing perfect
mustn't I have been alternating? mustn't you have been alternating? mustn't he have been alternating? mustn't we have been alternating? mustn't you have been alternating? mustn't they have been alternating?