must dumbfound
Regular verb: dumbfound - dumbfounded- dumbfounded

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must dumbfound
you must dumbfound
she must dumbfound
we must dumbfound
you must dumbfound
they must dumbfound 	I must be dumbfounding
you must be dumbfounding
she must be dumbfounding
we must be dumbfounding
you must be dumbfounding
they must be dumbfounding	I must have dumbfounded
you must have dumbfounded
she must have dumbfounded
we must have dumbfounded
you must have dumbfounded
they must have dumbfounded	I must have been dumbfounding
you must have been dumbfounding
she must have been dumbfounding
we must have been dumbfounding
you must have been dumbfounding
they must have been dumbfounding	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not dumbfound
you must not dumbfound
she must not dumbfound
we must not dumbfound
you must not dumbfound
they must not dumbfound 	I must not be dumbfounding
you must not be dumbfounding
she must not be dumbfounding
we must not be dumbfounding
you must not be dumbfounding
they must not be dumbfounding	I must not have dumbfounded
you must not have dumbfounded
she must not have dumbfounded
we must not have dumbfounded
you must not have dumbfounded
they must not have dumbfounded	I must not have been dumbfounding
you must not have been dumbfounding
she must not have been dumbfounding
we must not have been dumbfounding
you must not have been dumbfounding
they must not have been dumbfounding	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I dumbfound?
must you dumbfound?
must she dumbfound?
must we dumbfound?
must you dumbfound?
must they dumbfound? 	must I be dumbfounding?
must you be dumbfounding?
must she be dumbfounding?
must we be dumbfounding?
must you be dumbfounding?
must they be dumbfounding? 	must I have dumbfounded?
must you have dumbfounded?
must she have dumbfounded?
must we have dumbfounded?
must you have dumbfounded?
must they have dumbfounded? 	must I have been dumbfounding?
must you have been dumbfounding?
must she have been dumbfounding?
must we have been dumbfounding?
must you have been dumbfounding?
must they have been dumbfounding? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not dumbfound?
must you not dumbfound?
must she not dumbfound?
must we not dumbfound?
must you not dumbfound?
must they not dumbfound? 	must I not be dumbfounding?
must you not be dumbfounding?
must she not be dumbfounding?
must we not be dumbfounding?
must you not be dumbfounding?
must they not be dumbfounding? 	must I not have dumbfounded?
must you not have dumbfounded?
must she not have dumbfounded?
must we not have dumbfounded?
must you not have dumbfounded?
must they not have dumbfounded? 	must I not have been dumbfounding?
must you not have been dumbfounding?
must she not have been dumbfounding?
must we not have been dumbfounding?
must you not have been dumbfounding?
must they not have been dumbfounding?