could attest
Regular verb: attest - attested- attested

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could attest
you could attest
he could attest
we could attest
you could attest
they could attest 	I could be attesting
you could be attesting
he could be attesting
we could be attesting
you could be attesting
they could be attesting	I could have attested
you could have attested
he could have attested
we could have attested
you could have attested
they could have attested	I could have been attesting
you could have been attesting
he could have been attesting
we could have been attesting
you could have been attesting
they could have been attesting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not attest
you could not attest
he could not attest
we could not attest
you could not attest
they could not attest 	I could not be attesting
you could not be attesting
he could not be attesting
we could not be attesting
you could not be attesting
they could not be attesting	I could not have attested
you could not have attested
he could not have attested
we could not have attested
you could not have attested
they could not have attested	I could not have been attesting
you could not have been attesting
he could not have been attesting
we could not have been attesting
you could not have been attesting
they could not have been attesting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I attest?
could you attest?
could he attest?
could we attest?
could you attest?
could they attest? 	could I be attesting?
could you be attesting?
could he be attesting?
could we be attesting?
could you be attesting?
could they be attesting? 	could I have attested?
could you have attested?
could he have attested?
could we have attested?
could you have attested?
could they have attested? 	could I have been attesting?
could you have been attesting?
could he have been attesting?
could we have been attesting?
could you have been attesting?
could they have been attesting? 	

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