I could forefend you could forefend he could forefend we could forefend you could forefend they could forefend
V-ing form
I could be forefending you could be forefending he could be forefending we could be forefending you could be forefending they could be forefending
Perfect
I could have forefended you could have forefended he 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 he 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 he 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 he 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 he 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 he 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 he forefend? could we forefend? could you forefend? could they forefend?
V-ing form
could I be forefending? could you be forefending? could he be forefending? could we be forefending? could you be forefending? could they be forefending?
Perfect
could I have forefended? could you have forefended? could he 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 he 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 he 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 he 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 he 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 he have been forefending? couldn't we have been forefending? couldn't you have been forefending? couldn't they have been forefending?