I can append you can append he can append we can append you can append they can append
V-ing form
I can be appending you can be appending he can be appending we can be appending you can be appending they can be appending
Perfect
I can have appended you can have appended he can have appended we can have appended you can have appended they can have appended
V-ing perfect
I can have been appending you can have been appending he can have been appending we can have been appending you can have been appending they can have been appending
Negation
Simple form
I cannot append you cannot append he cannot append we cannot append you cannot append they cannot append
V-ing form
I cannot be appending you cannot be appending he cannot be appending we cannot be appending you cannot be appending they cannot be appending
Perfect
I cannot have appended you cannot have appended he cannot have appended we cannot have appended you cannot have appended they cannot have appended
V-ing perfect
I cannot have been appending you cannot have been appending he cannot have been appending we cannot have been appending you cannot have been appending they cannot have been appending
Interrogative form
Simple form
can I append? can you append? can he append? can we append? can you append? can they append?
V-ing form
can I be appending? can you be appending? can he be appending? can we be appending? can you be appending? can they be appending?
Perfect
can I have appended? can you have appended? can he have appended? can we have appended? can you have appended? can they have appended?
V-ing perfect
can I have been appending? can you have been appending? can he have been appending? can we have been appending? can you have been appending? can they have been appending?
Interro-negative form
Simple form
can I not append? can you not append? can he not append? can we not append? can you not append? can they not append?
V-ing form
can I not be appending? can you not be appending? can he not be appending? can we not be appending? can you not be appending? can they not be appending?
Perfect
can I not have appended? can you not have appended? can he not have appended? can we not have appended? can you not have appended? can they not have appended?
V-ing perfect
can I not have been appending? can you not have been appending? can he not have been appending? can we not have been appending? can you not have been appending? can they not have been appending?