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