ought to intervene
Regular verb: intervene - intervened- intervened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I ought to intervene
you ought to intervene
he ought to intervene
we ought to intervene
you ought to intervene
they ought to intervene 	I ought to be intervening
you ought to be intervening
he ought to be intervening
we ought to be intervening
you ought to be intervening
they ought to be intervening	I ought to have intervened
you ought to have intervened
he ought to have intervened
we ought to have intervened
you ought to have intervened
they ought to have intervened	I ought to have been intervening
you ought to have been intervening
he ought to have been intervening
we ought to have been intervening
you ought to have been intervening
they ought to have been intervening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I ought not to intervene
you ought not to intervene
he ought not to intervene
we ought not to intervene
you ought not to intervene
they ought not to intervene 	I ought not to intervening
you ought not to intervening
he ought not to intervening
we ought not to intervening
you ought not to intervening
they ought not to intervening	I ought not to have intervened
you ought not to have intervened
he ought not to have intervened
we ought not to have intervened
you ought not to have intervened
they ought not to have intervened	I ought not to have been intervening
you ought not to have been intervening
he ought not to have been intervening
we ought not to have been intervening
you ought not to have been intervening
they ought not to have been intervening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
ought to I intervene?
ought to you intervene?
ought to he intervene?
ought to we intervene?
ought to you intervene?
ought to they intervene? 	ought to I be intervening?
ought to you be intervening?
ought to he be intervening?
ought to we be intervening?
ought to you be intervening?
ought to they be intervening? 	ought to I have intervened?
ought to you have intervened?
ought to he have intervened?
ought to we have intervened?
ought to you have intervened?
ought to they have intervened? 	ought to I have been intervening?
ought to you have been intervening?
ought to he have been intervening?
ought to we have been intervening?
ought to you have been intervening?
ought to they have been intervening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
ought I not to intervene?
ought you not to intervene?
ought he not to intervene?
ought we not to intervene?
ought you not to intervene?
ought they not to intervene? 	ought I not to be intervening?
ought you not to be intervening?
ought he not to be intervening?
ought we not to be intervening?
ought you not to be intervening?
ought they not to be intervening? 	ought I not to have intervened?
ought you not to have intervened?
ought he not to have intervened?
ought we not to have intervened?
ought you not to have intervened?
ought they not to have intervened? 	ought I not to have been intervening?
ought you not to have been intervening?
ought he not to have been intervening?
ought we not to have been intervening?
ought you not to have been intervening?
ought they not to have been intervening?