I must switch you must switch she must switch we must switch you must switch they must switch
V-ing form
I must be switching you must be switching she must be switching we must be switching you must be switching they must be switching
Perfect
I must have switched you must have switched she must have switched we must have switched you must have switched they must have switched
V-ing perfect
I must have been switching you must have been switching she must have been switching we must have been switching you must have been switching they must have been switching
Negation
Simple form
I mustn't switch you mustn't switch she mustn't switch we mustn't switch you mustn't switch they mustn't switch
V-ing form
I mustn't be switching you mustn't be switching she mustn't be switching we mustn't be switching you mustn't be switching they mustn't be switching
Perfect
I mustn't have switched you mustn't have switched she mustn't have switched we mustn't have switched you mustn't have switched they mustn't have switched
V-ing perfect
I mustn't have been switching you mustn't have been switching she mustn't have been switching we mustn't have been switching you mustn't have been switching they mustn't have been switching
Interrogative form
Simple form
must I switch? must you switch? must she switch? must we switch? must you switch? must they switch?
V-ing form
must I be switching? must you be switching? must she be switching? must we be switching? must you be switching? must they be switching?
Perfect
must I have switched? must you have switched? must she have switched? must we have switched? must you have switched? must they have switched?
V-ing perfect
must I have been switching? must you have been switching? must she have been switching? must we have been switching? must you have been switching? must they have been switching?
Interro-negative form
Simple form
mustn't I switch? mustn't you switch? mustn't she switch? mustn't we switch? mustn't you switch? mustn't they switch?
V-ing form
mustn't I be switching? mustn't you be switching? mustn't she be switching? mustn't we be switching? mustn't you be switching? mustn't they be switching?
Perfect
mustn't I have switched? mustn't you have switched? mustn't she have switched? mustn't we have switched? mustn't you have switched? mustn't they have switched?
V-ing perfect
mustn't I have been switching? mustn't you have been switching? mustn't she have been switching? mustn't we have been switching? mustn't you have been switching? mustn't they have been switching?