could perceive
Regular verb: perceive - perceived- perceived

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

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not perceive
you could not perceive
she could not perceive
we could not perceive
you could not perceive
they could not perceive 	I could not be perceiving
you could not be perceiving
she could not be perceiving
we could not be perceiving
you could not be perceiving
they could not be perceiving	I could not have perceived
you could not have perceived
she could not have perceived
we could not have perceived
you could not have perceived
they could not have perceived	I could not have been perceiving
you could not have been perceiving
she could not have been perceiving
we could not have been perceiving
you could not have been perceiving
they could not have been perceiving	

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

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