I can attest you can attest he can attest we can attest you can attest they can attest
V-ing form
I can be attesting you can be attesting he can be attesting we can be attesting you can be attesting they can be attesting
Perfect
I can have attested you can have attested he can have attested we can have attested you can have attested they can have attested
V-ing perfect
I can have been attesting you can have been attesting he can have been attesting we can have been attesting you can have been attesting they can have been attesting
Negation
Simple form
I cannot attest you cannot attest he cannot attest we cannot attest you cannot attest they cannot attest
V-ing form
I cannot be attesting you cannot be attesting he cannot be attesting we cannot be attesting you cannot be attesting they cannot be attesting
Perfect
I cannot have attested you cannot have attested he cannot have attested we cannot have attested you cannot have attested they cannot have attested
V-ing perfect
I cannot have been attesting you cannot have been attesting he cannot have been attesting we cannot have been attesting you cannot have been attesting they cannot have been attesting
Interrogative form
Simple form
can I attest? can you attest? can he attest? can we attest? can you attest? can they attest?
V-ing form
can I be attesting? can you be attesting? can he be attesting? can we be attesting? can you be attesting? can they be attesting?
Perfect
can I have attested? can you have attested? can he have attested? can we have attested? can you have attested? can they have attested?
V-ing perfect
can I have been attesting? can you have been attesting? can he have been attesting? can we have been attesting? can you have been attesting? can they have been attesting?
Interro-negative form
Simple form
can I not attest? can you not attest? can he not attest? can we not attest? can you not attest? can they not attest?
V-ing form
can I not be attesting? can you not be attesting? can he not be attesting? can we not be attesting? can you not be attesting? can they not be attesting?
Perfect
can I not have attested? can you not have attested? can he not have attested? can we not have attested? can you not have attested? can they not have attested?
V-ing perfect
can I not have been attesting? can you not have been attesting? can he not have been attesting? can we not have been attesting? can you not have been attesting? can they not have been attesting?