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