I can testify you can testify he can testify we can testify you can testify they can testify
V-ing form
I can be testifying you can be testifying he can be testifying we can be testifying you can be testifying they can be testifying
Perfect
I can have testified you can have testified he can have testified we can have testified you can have testified they can have testified
V-ing perfect
I can have been testifying you can have been testifying he can have been testifying we can have been testifying you can have been testifying they can have been testifying
Negation
Simple form
I cannot testify you cannot testify he cannot testify we cannot testify you cannot testify they cannot testify
V-ing form
I cannot be testifying you cannot be testifying he cannot be testifying we cannot be testifying you cannot be testifying they cannot be testifying
Perfect
I cannot have testified you cannot have testified he cannot have testified we cannot have testified you cannot have testified they cannot have testified
V-ing perfect
I cannot have been testifying you cannot have been testifying he cannot have been testifying we cannot have been testifying you cannot have been testifying they cannot have been testifying
Interrogative form
Simple form
can I testify? can you testify? can he testify? can we testify? can you testify? can they testify?
V-ing form
can I be testifying? can you be testifying? can he be testifying? can we be testifying? can you be testifying? can they be testifying?
Perfect
can I have testified? can you have testified? can he have testified? can we have testified? can you have testified? can they have testified?
V-ing perfect
can I have been testifying? can you have been testifying? can he have been testifying? can we have been testifying? can you have been testifying? can they have been testifying?
Interro-negative form
Simple form
can I not testify? can you not testify? can he not testify? can we not testify? can you not testify? can they not testify?
V-ing form
can I not be testifying? can you not be testifying? can he not be testifying? can we not be testifying? can you not be testifying? can they not be testifying?
Perfect
can I not have testified? can you not have testified? can he not have testified? can we not have testified? can you not have testified? can they not have testified?
V-ing perfect
can I not have been testifying? can you not have been testifying? can he not have been testifying? can we not have been testifying? can you not have been testifying? can they not have been testifying?