I can testify you can testify she can testify we can testify you can testify they can testify
V-ing form
I can be testifying you can be testifying she can be testifying we can be testifying you can be testifying they can be testifying
Perfect
I can have testified you can have testified she 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 she 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 she cannot testify we cannot testify you cannot testify they cannot testify
V-ing form
I cannot be testifying you cannot be testifying she cannot be testifying we cannot be testifying you cannot be testifying they cannot be testifying
Perfect
I cannot have testified you cannot have testified she 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 she 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 she testify? can we testify? can you testify? can they testify?
V-ing form
can I be testifying? can you be testifying? can she be testifying? can we be testifying? can you be testifying? can they be testifying?
Perfect
can I have testified? can you have testified? can she 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 she 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 she 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 she 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 she 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 she not have been testifying? can we not have been testifying? can you not have been testifying? can they not have been testifying?