English verb conjugation
CAN ATTEST

Regular verb: attest - attested - attested

Affirmation

Simple form	V-ing form
I can attest you can attest he can attest we can attest you can attest they can attest	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	V-ing 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	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	V-ing form
I can't attest you can't attest he can't attest we can't attest you can't attest they can't attest	I can't be attesting you can't be attesting he can't be attesting we can't be attesting you can't be attesting they can't be attesting
Perfect	V-ing perfect
I can't have attested you can't have attested he can't have attested we can't have attested you can't have attested they can't have attested	I can't have been attesting you can't have been attesting he can't have been attesting we can't have been attesting you can't have been attesting they can't have been attesting

Interrogative form

Simple form	V-ing form
can I attest? can you attest? can he attest? can we attest? can you attest? can they attest?	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	V-ing 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?	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	V-ing form
can't I attest? can't you attest? can't he attest? can't we attest? can't you attest? can't they attest?	can't I be attesting? can't you be attesting? can't he be attesting? can't we be attesting? can't you be attesting? can't they be attesting?
Perfect	V-ing perfect
can't I have attested? can't you have attested? can't he have attested? can't we have attested? can't you have attested? can't they have attested?	can't I have been attesting? can't you have been attesting? can't he have been attesting? can't we have been attesting? can't you have been attesting? can't they have been attesting?