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