must intervene
Verbo regular: intervene - intervened- intervened

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must intervene
you must intervene
she must intervene
we must intervene
you must intervene
they must intervene 	I must be intervening
you must be intervening
she must be intervening
we must be intervening
you must be intervening
they must be intervening	I must have intervened
you must have intervened
she must have intervened
we must have intervened
you must have intervened
they must have intervened	I must have been intervening
you must have been intervening
she must have been intervening
we must have been intervening
you must have been intervening
they must have been intervening	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not intervene
you must not intervene
she must not intervene
we must not intervene
you must not intervene
they must not intervene 	I must not be intervening
you must not be intervening
she must not be intervening
we must not be intervening
you must not be intervening
they must not be intervening	I must not have intervened
you must not have intervened
she must not have intervened
we must not have intervened
you must not have intervened
they must not have intervened	I must not have been intervening
you must not have been intervening
she must not have been intervening
we must not have been intervening
you must not have been intervening
they must not have been intervening	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I intervene?
must you intervene?
must she intervene?
must we intervene?
must you intervene?
must they intervene? 	must I be intervening?
must you be intervening?
must she be intervening?
must we be intervening?
must you be intervening?
must they be intervening? 	must I have intervened?
must you have intervened?
must she have intervened?
must we have intervened?
must you have intervened?
must they have intervened? 	must I have been intervening?
must you have been intervening?
must she have been intervening?
must we have been intervening?
must you have been intervening?
must they have been intervening? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not intervene?
must you not intervene?
must she not intervene?
must we not intervene?
must you not intervene?
must they not intervene? 	must I not be intervening?
must you not be intervening?
must she not be intervening?
must we not be intervening?
must you not be intervening?
must they not be intervening? 	must I not have intervened?
must you not have intervened?
must she not have intervened?
must we not have intervened?
must you not have intervened?
must they not have intervened? 	must I not have been intervening?
must you not have been intervening?
must she not have been intervening?
must we not have been intervening?
must you not have been intervening?
must they not have been intervening?