must decolourise
Regular verb: decolourise - decolourised- decolourised

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must decolourise
you must decolourise
he must decolourise
we must decolourise
you must decolourise
they must decolourise 	I must be decolourising
you must be decolourising
he must be decolourising
we must be decolourising
you must be decolourising
they must be decolourising	I must have decolourised
you must have decolourised
he must have decolourised
we must have decolourised
you must have decolourised
they must have decolourised	I must have been decolourising
you must have been decolourising
he must have been decolourising
we must have been decolourising
you must have been decolourising
they must have been decolourising	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't decolourise
you mustn't decolourise
he mustn't decolourise
we mustn't decolourise
you mustn't decolourise
they mustn't decolourise 	I mustn't be decolourising
you mustn't be decolourising
he mustn't be decolourising
we mustn't be decolourising
you mustn't be decolourising
they mustn't be decolourising	I mustn't have decolourised
you mustn't have decolourised
he mustn't have decolourised
we mustn't have decolourised
you mustn't have decolourised
they mustn't have decolourised	I mustn't have been decolourising
you mustn't have been decolourising
he mustn't have been decolourising
we mustn't have been decolourising
you mustn't have been decolourising
they mustn't have been decolourising	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I decolourise?
must you decolourise?
must he decolourise?
must we decolourise?
must you decolourise?
must they decolourise? 	must I be decolourising?
must you be decolourising?
must he be decolourising?
must we be decolourising?
must you be decolourising?
must they be decolourising? 	must I have decolourised?
must you have decolourised?
must he have decolourised?
must we have decolourised?
must you have decolourised?
must they have decolourised? 	must I have been decolourising?
must you have been decolourising?
must he have been decolourising?
must we have been decolourising?
must you have been decolourising?
must they have been decolourising? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I decolourise?
mustn't you decolourise?
mustn't he decolourise?
mustn't we decolourise?
mustn't you decolourise?
mustn't they decolourise? 	mustn't I be decolourising?
mustn't you be decolourising?
mustn't he be decolourising?
mustn't we be decolourising?
mustn't you be decolourising?
mustn't they be decolourising? 	mustn't I have decolourised?
mustn't you have decolourised?
mustn't he have decolourised?
mustn't we have decolourised?
mustn't you have decolourised?
mustn't they have decolourised? 	mustn't I have been decolourising?
mustn't you have been decolourising?
mustn't he have been decolourising?
mustn't we have been decolourising?
mustn't you have been decolourising?
mustn't they have been decolourising?