must threaten
Regular verb: threaten - threatened- threatened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must threaten
you must threaten
he must threaten
we must threaten
you must threaten
they must threaten 	I must be threatening
you must be threatening
he must be threatening
we must be threatening
you must be threatening
they must be threatening	I must have threatened
you must have threatened
he must have threatened
we must have threatened
you must have threatened
they must have threatened	I must have been threatening
you must have been threatening
he must have been threatening
we must have been threatening
you must have been threatening
they must have been threatening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not threaten
you must not threaten
he must not threaten
we must not threaten
you must not threaten
they must not threaten 	I must not be threatening
you must not be threatening
he must not be threatening
we must not be threatening
you must not be threatening
they must not be threatening	I must not have threatened
you must not have threatened
he must not have threatened
we must not have threatened
you must not have threatened
they must not have threatened	I must not have been threatening
you must not have been threatening
he must not have been threatening
we must not have been threatening
you must not have been threatening
they must not have been threatening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I threaten?
must you threaten?
must he threaten?
must we threaten?
must you threaten?
must they threaten? 	must I be threatening?
must you be threatening?
must he be threatening?
must we be threatening?
must you be threatening?
must they be threatening? 	must I have threatened?
must you have threatened?
must he have threatened?
must we have threatened?
must you have threatened?
must they have threatened? 	must I have been threatening?
must you have been threatening?
must he have been threatening?
must we have been threatening?
must you have been threatening?
must they have been threatening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not threaten?
must you not threaten?
must he not threaten?
must we not threaten?
must you not threaten?
must they not threaten? 	must I not be threatening?
must you not be threatening?
must he not be threatening?
must we not be threatening?
must you not be threatening?
must they not be threatening? 	must I not have threatened?
must you not have threatened?
must he not have threatened?
must we not have threatened?
must you not have threatened?
must they not have threatened? 	must I not have been threatening?
must you not have been threatening?
must he not have been threatening?
must we not have been threatening?
must you not have been threatening?
must they not have been threatening?