I can fend you can fend he can fend we can fend you can fend they can fend
V-ing form
I can be fending you can be fending he can be fending we can be fending you can be fending they can be fending
Perfect
I can have fended you can have fended he can have fended we can have fended you can have fended they can have fended
V-ing perfect
I can have been fending you can have been fending he can have been fending we can have been fending you can have been fending they can have been fending
Negation
Simple form
I cannot fend you cannot fend he cannot fend we cannot fend you cannot fend they cannot fend
V-ing form
I cannot be fending you cannot be fending he cannot be fending we cannot be fending you cannot be fending they cannot be fending
Perfect
I cannot have fended you cannot have fended he cannot have fended we cannot have fended you cannot have fended they cannot have fended
V-ing perfect
I cannot have been fending you cannot have been fending he cannot have been fending we cannot have been fending you cannot have been fending they cannot have been fending
Interrogative form
Simple form
can I fend? can you fend? can he fend? can we fend? can you fend? can they fend?
V-ing form
can I be fending? can you be fending? can he be fending? can we be fending? can you be fending? can they be fending?
Perfect
can I have fended? can you have fended? can he have fended? can we have fended? can you have fended? can they have fended?
V-ing perfect
can I have been fending? can you have been fending? can he have been fending? can we have been fending? can you have been fending? can they have been fending?
Interro-negative form
Simple form
can I not fend? can you not fend? can he not fend? can we not fend? can you not fend? can they not fend?
V-ing form
can I not be fending? can you not be fending? can he not be fending? can we not be fending? can you not be fending? can they not be fending?
Perfect
can I not have fended? can you not have fended? can he not have fended? can we not have fended? can you not have fended? can they not have fended?
V-ing perfect
can I not have been fending? can you not have been fending? can he not have been fending? can we not have been fending? can you not have been fending? can they not have been fending?