must frustrate
Regular verb: frustrate - frustrated- frustrated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must frustrate
you must frustrate
he must frustrate
we must frustrate
you must frustrate
they must frustrate 	I must be frustrating
you must be frustrating
he must be frustrating
we must be frustrating
you must be frustrating
they must be frustrating	I must have frustrated
you must have frustrated
he must have frustrated
we must have frustrated
you must have frustrated
they must have frustrated	I must have been frustrating
you must have been frustrating
he must have been frustrating
we must have been frustrating
you must have been frustrating
they must have been frustrating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not frustrate
you must not frustrate
he must not frustrate
we must not frustrate
you must not frustrate
they must not frustrate 	I must not be frustrating
you must not be frustrating
he must not be frustrating
we must not be frustrating
you must not be frustrating
they must not be frustrating	I must not have frustrated
you must not have frustrated
he must not have frustrated
we must not have frustrated
you must not have frustrated
they must not have frustrated	I must not have been frustrating
you must not have been frustrating
he must not have been frustrating
we must not have been frustrating
you must not have been frustrating
they must not have been frustrating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I frustrate?
must you frustrate?
must he frustrate?
must we frustrate?
must you frustrate?
must they frustrate? 	must I be frustrating?
must you be frustrating?
must he be frustrating?
must we be frustrating?
must you be frustrating?
must they be frustrating? 	must I have frustrated?
must you have frustrated?
must he have frustrated?
must we have frustrated?
must you have frustrated?
must they have frustrated? 	must I have been frustrating?
must you have been frustrating?
must he have been frustrating?
must we have been frustrating?
must you have been frustrating?
must they have been frustrating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not frustrate?
must you not frustrate?
must he not frustrate?
must we not frustrate?
must you not frustrate?
must they not frustrate? 	must I not be frustrating?
must you not be frustrating?
must he not be frustrating?
must we not be frustrating?
must you not be frustrating?
must they not be frustrating? 	must I not have frustrated?
must you not have frustrated?
must he not have frustrated?
must we not have frustrated?
must you not have frustrated?
must they not have frustrated? 	must I not have been frustrating?
must you not have been frustrating?
must he not have been frustrating?
must we not have been frustrating?
must you not have been frustrating?
must they not have been frustrating?