I could forefend you could forefend she could forefend we could forefend you could forefend they could forefend
V-ing form
I could be forefending you could be forefending she could be forefending we could be forefending you could be forefending they could be forefending
Perfect
I could have forefended you could have forefended she could have forefended we could have forefended you could have forefended they could have forefended
V-ing perfect
I could have been forefending you could have been forefending she could have been forefending we could have been forefending you could have been forefending they could have been forefending
Negation
Simple form
I couldn't forefend you couldn't forefend she couldn't forefend we couldn't forefend you couldn't forefend they couldn't forefend
V-ing form
I couldn't be forefending you couldn't be forefending she couldn't be forefending we couldn't be forefending you couldn't be forefending they couldn't be forefending
Perfect
I couldn't have forefended you couldn't have forefended she couldn't have forefended we couldn't have forefended you couldn't have forefended they couldn't have forefended
V-ing perfect
I couldn't have been forefending you couldn't have been forefending she couldn't have been forefending we couldn't have been forefending you couldn't have been forefending they couldn't have been forefending
Interrogative form
Simple form
could I forefend? could you forefend? could she forefend? could we forefend? could you forefend? could they forefend?
V-ing form
could I be forefending? could you be forefending? could she be forefending? could we be forefending? could you be forefending? could they be forefending?
Perfect
could I have forefended? could you have forefended? could she have forefended? could we have forefended? could you have forefended? could they have forefended?
V-ing perfect
could I have been forefending? could you have been forefending? could she have been forefending? could we have been forefending? could you have been forefending? could they have been forefending?
Interro-negative form
Simple form
couldn't I forefend? couldn't you forefend? couldn't she forefend? couldn't we forefend? couldn't you forefend? couldn't they forefend?
V-ing form
couldn't I be forefending? couldn't you be forefending? couldn't she be forefending? couldn't we be forefending? couldn't you be forefending? couldn't they be forefending?
Perfect
couldn't I have forefended? couldn't you have forefended? couldn't she have forefended? couldn't we have forefended? couldn't you have forefended? couldn't they have forefended?
V-ing perfect
couldn't I have been forefending? couldn't you have been forefending? couldn't she have been forefending? couldn't we have been forefending? couldn't you have been forefending? couldn't they have been forefending?