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 cannot forefend you cannot forefend he cannot forefend we cannot forefend you cannot forefend they cannot forefend
V-ing form
I cannot be forefending you cannot be forefending he cannot be forefending we cannot be forefending you cannot be forefending they cannot be forefending
Perfect
I cannot have forefended you cannot have forefended he cannot have forefended we cannot have forefended you cannot have forefended they cannot have forefended
V-ing perfect
I cannot have been forefending you cannot have been forefending he cannot have been forefending we cannot have been forefending you cannot have been forefending they cannot 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 I not forefend? can you not forefend? can he not forefend? can we not forefend? can you not forefend? can they not forefend?
V-ing form
can I not be forefending? can you not be forefending? can he not be forefending? can we not be forefending? can you not be forefending? can they not be forefending?
Perfect
can I not have forefended? can you not have forefended? can he not have forefended? can we not have forefended? can you not have forefended? can they not have forefended?
V-ing perfect
can I not have been forefending? can you not have been forefending? can he not have been forefending? can we not have been forefending? can you not have been forefending? can they not have been forefending?