must interfuse
Regular verb: interfuse - interfused- interfused

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must interfuse
you must interfuse
she must interfuse
we must interfuse
you must interfuse
they must interfuse 	I must be interfusing
you must be interfusing
she must be interfusing
we must be interfusing
you must be interfusing
they must be interfusing	I must have interfused
you must have interfused
she must have interfused
we must have interfused
you must have interfused
they must have interfused	I must have been interfusing
you must have been interfusing
she must have been interfusing
we must have been interfusing
you must have been interfusing
they must have been interfusing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't interfuse
you mustn't interfuse
she mustn't interfuse
we mustn't interfuse
you mustn't interfuse
they mustn't interfuse 	I mustn't be interfusing
you mustn't be interfusing
she mustn't be interfusing
we mustn't be interfusing
you mustn't be interfusing
they mustn't be interfusing	I mustn't have interfused
you mustn't have interfused
she mustn't have interfused
we mustn't have interfused
you mustn't have interfused
they mustn't have interfused	I mustn't have been interfusing
you mustn't have been interfusing
she mustn't have been interfusing
we mustn't have been interfusing
you mustn't have been interfusing
they mustn't have been interfusing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I interfuse?
must you interfuse?
must she interfuse?
must we interfuse?
must you interfuse?
must they interfuse? 	must I be interfusing?
must you be interfusing?
must she be interfusing?
must we be interfusing?
must you be interfusing?
must they be interfusing? 	must I have interfused?
must you have interfused?
must she have interfused?
must we have interfused?
must you have interfused?
must they have interfused? 	must I have been interfusing?
must you have been interfusing?
must she have been interfusing?
must we have been interfusing?
must you have been interfusing?
must they have been interfusing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I interfuse?
mustn't you interfuse?
mustn't she interfuse?
mustn't we interfuse?
mustn't you interfuse?
mustn't they interfuse? 	mustn't I be interfusing?
mustn't you be interfusing?
mustn't she be interfusing?
mustn't we be interfusing?
mustn't you be interfusing?
mustn't they be interfusing? 	mustn't I have interfused?
mustn't you have interfused?
mustn't she have interfused?
mustn't we have interfused?
mustn't you have interfused?
mustn't they have interfused? 	mustn't I have been interfusing?
mustn't you have been interfusing?
mustn't she have been interfusing?
mustn't we have been interfusing?
mustn't you have been interfusing?
mustn't they have been interfusing?