I can friend you can friend he can friend we can friend you can friend they can friend
V-ing form
I can be friending you can be friending he can be friending we can be friending you can be friending they can be friending
Perfect
I can have friended you can have friended he can have friended we can have friended you can have friended they can have friended
V-ing perfect
I can have been friending you can have been friending he can have been friending we can have been friending you can have been friending they can have been friending
Negation
Simple form
I cannot friend you cannot friend he cannot friend we cannot friend you cannot friend they cannot friend
V-ing form
I cannot be friending you cannot be friending he cannot be friending we cannot be friending you cannot be friending they cannot be friending
Perfect
I cannot have friended you cannot have friended he cannot have friended we cannot have friended you cannot have friended they cannot have friended
V-ing perfect
I cannot have been friending you cannot have been friending he cannot have been friending we cannot have been friending you cannot have been friending they cannot have been friending
Interrogative form
Simple form
can I friend? can you friend? can he friend? can we friend? can you friend? can they friend?
V-ing form
can I be friending? can you be friending? can he be friending? can we be friending? can you be friending? can they be friending?
Perfect
can I have friended? can you have friended? can he have friended? can we have friended? can you have friended? can they have friended?
V-ing perfect
can I have been friending? can you have been friending? can he have been friending? can we have been friending? can you have been friending? can they have been friending?
Interro-negative form
Simple form
can I not friend? can you not friend? can he not friend? can we not friend? can you not friend? can they not friend?
V-ing form
can I not be friending? can you not be friending? can he not be friending? can we not be friending? can you not be friending? can they not be friending?
Perfect
can I not have friended? can you not have friended? can he not have friended? can we not have friended? can you not have friended? can they not have friended?
V-ing perfect
can I not have been friending? can you not have been friending? can he not have been friending? can we not have been friending? can you not have been friending? can they not have been friending?