must check
Regular verb: check - checked- checked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must check
you must check
she must check
we must check
you must check
they must check 	I must be checking
you must be checking
she must be checking
we must be checking
you must be checking
they must be checking	I must have checked
you must have checked
she must have checked
we must have checked
you must have checked
they must have checked	I must have been checking
you must have been checking
she must have been checking
we must have been checking
you must have been checking
they must have been checking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't check
you mustn't check
she mustn't check
we mustn't check
you mustn't check
they mustn't check 	I mustn't be checking
you mustn't be checking
she mustn't be checking
we mustn't be checking
you mustn't be checking
they mustn't be checking	I mustn't have checked
you mustn't have checked
she mustn't have checked
we mustn't have checked
you mustn't have checked
they mustn't have checked	I mustn't have been checking
you mustn't have been checking
she mustn't have been checking
we mustn't have been checking
you mustn't have been checking
they mustn't have been checking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I check?
must you check?
must she check?
must we check?
must you check?
must they check? 	must I be checking?
must you be checking?
must she be checking?
must we be checking?
must you be checking?
must they be checking? 	must I have checked?
must you have checked?
must she have checked?
must we have checked?
must you have checked?
must they have checked? 	must I have been checking?
must you have been checking?
must she have been checking?
must we have been checking?
must you have been checking?
must they have been checking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I check?
mustn't you check?
mustn't she check?
mustn't we check?
mustn't you check?
mustn't they check? 	mustn't I be checking?
mustn't you be checking?
mustn't she be checking?
mustn't we be checking?
mustn't you be checking?
mustn't they be checking? 	mustn't I have checked?
mustn't you have checked?
mustn't she have checked?
mustn't we have checked?
mustn't you have checked?
mustn't they have checked? 	mustn't I have been checking?
mustn't you have been checking?
mustn't she have been checking?
mustn't we have been checking?
mustn't you have been checking?
mustn't they have been checking?