I must switch you must switch he must switch we must switch you must switch they must switch
V-ing form
I must be switching you must be switching he must be switching we must be switching you must be switching they must be switching
Perfect
I must have switched you must have switched he 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 he must have been switching we must have been switching you must have been switching they must have been switching
Negation
Simple form
I must not switch you must not switch he must not switch we must not switch you must not switch they must not switch
V-ing form
I must not be switching you must not be switching he must not be switching we must not be switching you must not be switching they must not be switching
Perfect
I must not have switched you must not have switched he must not have switched we must not have switched you must not have switched they must not have switched
V-ing perfect
I must not have been switching you must not have been switching he must not have been switching we must not have been switching you must not have been switching they must not have been switching
Interrogative form
Simple form
must I switch? must you switch? must he switch? must we switch? must you switch? must they switch?
V-ing form
must I be switching? must you be switching? must he be switching? must we be switching? must you be switching? must they be switching?
Perfect
must I have switched? must you have switched? must he 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 he have been switching? must we have been switching? must you have been switching? must they have been switching?
Interro-negative form
Simple form
must I not switch? must you not switch? must he not switch? must we not switch? must you not switch? must they not switch?
V-ing form
must I not be switching? must you not be switching? must he not be switching? must we not be switching? must you not be switching? must they not be switching?
Perfect
must I not have switched? must you not have switched? must he not have switched? must we not have switched? must you not have switched? must they not have switched?
V-ing perfect
must I not have been switching? must you not have been switching? must he not have been switching? must we not have been switching? must you not have been switching? must they not have been switching?