I could frequent you could frequent he could frequent we could frequent you could frequent they could frequent
V-ing form
I could be frequenting you could be frequenting he could be frequenting we could be frequenting you could be frequenting they could be frequenting
Perfect
I could have frequented you could have frequented he could have frequented we could have frequented you could have frequented they could have frequented
V-ing perfect
I could have been frequenting you could have been frequenting he could have been frequenting we could have been frequenting you could have been frequenting they could have been frequenting
Negation
Simple form
I couldn't frequent you couldn't frequent he couldn't frequent we couldn't frequent you couldn't frequent they couldn't frequent
V-ing form
I couldn't be frequenting you couldn't be frequenting he couldn't be frequenting we couldn't be frequenting you couldn't be frequenting they couldn't be frequenting
Perfect
I couldn't have frequented you couldn't have frequented he couldn't have frequented we couldn't have frequented you couldn't have frequented they couldn't have frequented
V-ing perfect
I couldn't have been frequenting you couldn't have been frequenting he couldn't have been frequenting we couldn't have been frequenting you couldn't have been frequenting they couldn't have been frequenting
Interrogative form
Simple form
could I frequent? could you frequent? could he frequent? could we frequent? could you frequent? could they frequent?
V-ing form
could I be frequenting? could you be frequenting? could he be frequenting? could we be frequenting? could you be frequenting? could they be frequenting?
Perfect
could I have frequented? could you have frequented? could he have frequented? could we have frequented? could you have frequented? could they have frequented?
V-ing perfect
could I have been frequenting? could you have been frequenting? could he have been frequenting? could we have been frequenting? could you have been frequenting? could they have been frequenting?
Interro-negative form
Simple form
couldn't I frequent? couldn't you frequent? couldn't he frequent? couldn't we frequent? couldn't you frequent? couldn't they frequent?
V-ing form
couldn't I be frequenting? couldn't you be frequenting? couldn't he be frequenting? couldn't we be frequenting? couldn't you be frequenting? couldn't they be frequenting?
Perfect
couldn't I have frequented? couldn't you have frequented? couldn't he have frequented? couldn't we have frequented? couldn't you have frequented? couldn't they have frequented?
V-ing perfect
couldn't I have been frequenting? couldn't you have been frequenting? couldn't he have been frequenting? couldn't we have been frequenting? couldn't you have been frequenting? couldn't they have been frequenting?