must underestimate
Regular verb: underestimate - underestimated- underestimated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must underestimate
you must underestimate
he must underestimate
we must underestimate
you must underestimate
they must underestimate 	I must be underestimating
you must be underestimating
he must be underestimating
we must be underestimating
you must be underestimating
they must be underestimating	I must have underestimated
you must have underestimated
he must have underestimated
we must have underestimated
you must have underestimated
they must have underestimated	I must have been underestimating
you must have been underestimating
he must have been underestimating
we must have been underestimating
you must have been underestimating
they must have been underestimating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't underestimate
you mustn't underestimate
he mustn't underestimate
we mustn't underestimate
you mustn't underestimate
they mustn't underestimate 	I mustn't be underestimating
you mustn't be underestimating
he mustn't be underestimating
we mustn't be underestimating
you mustn't be underestimating
they mustn't be underestimating	I mustn't have underestimated
you mustn't have underestimated
he mustn't have underestimated
we mustn't have underestimated
you mustn't have underestimated
they mustn't have underestimated	I mustn't have been underestimating
you mustn't have been underestimating
he mustn't have been underestimating
we mustn't have been underestimating
you mustn't have been underestimating
they mustn't have been underestimating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I underestimate?
must you underestimate?
must he underestimate?
must we underestimate?
must you underestimate?
must they underestimate? 	must I be underestimating?
must you be underestimating?
must he be underestimating?
must we be underestimating?
must you be underestimating?
must they be underestimating? 	must I have underestimated?
must you have underestimated?
must he have underestimated?
must we have underestimated?
must you have underestimated?
must they have underestimated? 	must I have been underestimating?
must you have been underestimating?
must he have been underestimating?
must we have been underestimating?
must you have been underestimating?
must they have been underestimating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I underestimate?
mustn't you underestimate?
mustn't he underestimate?
mustn't we underestimate?
mustn't you underestimate?
mustn't they underestimate? 	mustn't I be underestimating?
mustn't you be underestimating?
mustn't he be underestimating?
mustn't we be underestimating?
mustn't you be underestimating?
mustn't they be underestimating? 	mustn't I have underestimated?
mustn't you have underestimated?
mustn't he have underestimated?
mustn't we have underestimated?
mustn't you have underestimated?
mustn't they have underestimated? 	mustn't I have been underestimating?
mustn't you have been underestimating?
mustn't he have been underestimating?
mustn't we have been underestimating?
mustn't you have been underestimating?
mustn't they have been underestimating?