must decarburise
Regular verb: decarburise - decarburised- decarburised

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must decarburise
you must decarburise
she must decarburise
we must decarburise
you must decarburise
they must decarburise 	I must be decarburising
you must be decarburising
she must be decarburising
we must be decarburising
you must be decarburising
they must be decarburising	I must have decarburised
you must have decarburised
she must have decarburised
we must have decarburised
you must have decarburised
they must have decarburised	I must have been decarburising
you must have been decarburising
she must have been decarburising
we must have been decarburising
you must have been decarburising
they must have been decarburising	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not decarburise
you must not decarburise
she must not decarburise
we must not decarburise
you must not decarburise
they must not decarburise 	I must not be decarburising
you must not be decarburising
she must not be decarburising
we must not be decarburising
you must not be decarburising
they must not be decarburising	I must not have decarburised
you must not have decarburised
she must not have decarburised
we must not have decarburised
you must not have decarburised
they must not have decarburised	I must not have been decarburising
you must not have been decarburising
she must not have been decarburising
we must not have been decarburising
you must not have been decarburising
they must not have been decarburising	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I decarburise?
must you decarburise?
must she decarburise?
must we decarburise?
must you decarburise?
must they decarburise? 	must I be decarburising?
must you be decarburising?
must she be decarburising?
must we be decarburising?
must you be decarburising?
must they be decarburising? 	must I have decarburised?
must you have decarburised?
must she have decarburised?
must we have decarburised?
must you have decarburised?
must they have decarburised? 	must I have been decarburising?
must you have been decarburising?
must she have been decarburising?
must we have been decarburising?
must you have been decarburising?
must they have been decarburising? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not decarburise?
must you not decarburise?
must she not decarburise?
must we not decarburise?
must you not decarburise?
must they not decarburise? 	must I not be decarburising?
must you not be decarburising?
must she not be decarburising?
must we not be decarburising?
must you not be decarburising?
must they not be decarburising? 	must I not have decarburised?
must you not have decarburised?
must she not have decarburised?
must we not have decarburised?
must you not have decarburised?
must they not have decarburised? 	must I not have been decarburising?
must you not have been decarburising?
must she not have been decarburising?
must we not have been decarburising?
must you not have been decarburising?
must they not have been decarburising?