must perceive
Regular verb: perceive - perceived- perceived

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must perceive
you must perceive
she must perceive
we must perceive
you must perceive
they must perceive 	I must be perceiving
you must be perceiving
she must be perceiving
we must be perceiving
you must be perceiving
they must be perceiving	I must have perceived
you must have perceived
she must have perceived
we must have perceived
you must have perceived
they must have perceived	I must have been perceiving
you must have been perceiving
she must have been perceiving
we must have been perceiving
you must have been perceiving
they must have been perceiving	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't perceive
you mustn't perceive
she mustn't perceive
we mustn't perceive
you mustn't perceive
they mustn't perceive 	I mustn't be perceiving
you mustn't be perceiving
she mustn't be perceiving
we mustn't be perceiving
you mustn't be perceiving
they mustn't be perceiving	I mustn't have perceived
you mustn't have perceived
she mustn't have perceived
we mustn't have perceived
you mustn't have perceived
they mustn't have perceived	I mustn't have been perceiving
you mustn't have been perceiving
she mustn't have been perceiving
we mustn't have been perceiving
you mustn't have been perceiving
they mustn't have been perceiving	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I perceive?
must you perceive?
must she perceive?
must we perceive?
must you perceive?
must they perceive? 	must I be perceiving?
must you be perceiving?
must she be perceiving?
must we be perceiving?
must you be perceiving?
must they be perceiving? 	must I have perceived?
must you have perceived?
must she have perceived?
must we have perceived?
must you have perceived?
must they have perceived? 	must I have been perceiving?
must you have been perceiving?
must she have been perceiving?
must we have been perceiving?
must you have been perceiving?
must they have been perceiving? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I perceive?
mustn't you perceive?
mustn't she perceive?
mustn't we perceive?
mustn't you perceive?
mustn't they perceive? 	mustn't I be perceiving?
mustn't you be perceiving?
mustn't she be perceiving?
mustn't we be perceiving?
mustn't you be perceiving?
mustn't they be perceiving? 	mustn't I have perceived?
mustn't you have perceived?
mustn't she have perceived?
mustn't we have perceived?
mustn't you have perceived?
mustn't they have perceived? 	mustn't I have been perceiving?
mustn't you have been perceiving?
mustn't she have been perceiving?
mustn't we have been perceiving?
mustn't you have been perceiving?
mustn't they have been perceiving?