could button
Regular verb: button - buttoned- buttoned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could button
you could button
he could button
we could button
you could button
they could button 	I could be buttoning
you could be buttoning
he could be buttoning
we could be buttoning
you could be buttoning
they could be buttoning	I could have buttoned
you could have buttoned
he could have buttoned
we could have buttoned
you could have buttoned
they could have buttoned	I could have been buttoning
you could have been buttoning
he could have been buttoning
we could have been buttoning
you could have been buttoning
they could have been buttoning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not button
you could not button
he could not button
we could not button
you could not button
they could not button 	I could not be buttoning
you could not be buttoning
he could not be buttoning
we could not be buttoning
you could not be buttoning
they could not be buttoning	I could not have buttoned
you could not have buttoned
he could not have buttoned
we could not have buttoned
you could not have buttoned
they could not have buttoned	I could not have been buttoning
you could not have been buttoning
he could not have been buttoning
we could not have been buttoning
you could not have been buttoning
they could not have been buttoning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I button?
could you button?
could he button?
could we button?
could you button?
could they button? 	could I be buttoning?
could you be buttoning?
could he be buttoning?
could we be buttoning?
could you be buttoning?
could they be buttoning? 	could I have buttoned?
could you have buttoned?
could he have buttoned?
could we have buttoned?
could you have buttoned?
could they have buttoned? 	could I have been buttoning?
could you have been buttoning?
could he have been buttoning?
could we have been buttoning?
could you have been buttoning?
could they have been buttoning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not button?
could you not button?
could he not button?
could we not button?
could you not button?
could they not button? 	could I not be buttoning?
could you not be buttoning?
could he not be buttoning?
could we not be buttoning?
could you not be buttoning?
could they not be buttoning? 	could I not have buttoned?
could you not have buttoned?
could he not have buttoned?
could we not have buttoned?
could you not have buttoned?
could they not have buttoned? 	could I not have been buttoning?
could you not have been buttoning?
could he not have been buttoning?
could we not have been buttoning?
could you not have been buttoning?
could they not have been buttoning?