could ripen
Regular verb: ripen - ripened- ripened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could ripen
you could ripen
she could ripen
we could ripen
you could ripen
they could ripen 	I could be ripening
you could be ripening
she could be ripening
we could be ripening
you could be ripening
they could be ripening	I could have ripened
you could have ripened
she could have ripened
we could have ripened
you could have ripened
they could have ripened	I could have been ripening
you could have been ripening
she could have been ripening
we could have been ripening
you could have been ripening
they could have been ripening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not ripen
you could not ripen
she could not ripen
we could not ripen
you could not ripen
they could not ripen 	I could not be ripening
you could not be ripening
she could not be ripening
we could not be ripening
you could not be ripening
they could not be ripening	I could not have ripened
you could not have ripened
she could not have ripened
we could not have ripened
you could not have ripened
they could not have ripened	I could not have been ripening
you could not have been ripening
she could not have been ripening
we could not have been ripening
you could not have been ripening
they could not have been ripening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I ripen?
could you ripen?
could she ripen?
could we ripen?
could you ripen?
could they ripen? 	could I be ripening?
could you be ripening?
could she be ripening?
could we be ripening?
could you be ripening?
could they be ripening? 	could I have ripened?
could you have ripened?
could she have ripened?
could we have ripened?
could you have ripened?
could they have ripened? 	could I have been ripening?
could you have been ripening?
could she have been ripening?
could we have been ripening?
could you have been ripening?
could they have been ripening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not ripen?
could you not ripen?
could she not ripen?
could we not ripen?
could you not ripen?
could they not ripen? 	could I not be ripening?
could you not be ripening?
could she not be ripening?
could we not be ripening?
could you not be ripening?
could they not be ripening? 	could I not have ripened?
could you not have ripened?
could she not have ripened?
could we not have ripened?
could you not have ripened?
could they not have ripened? 	could I not have been ripening?
could you not have been ripening?
could she not have been ripening?
could we not have been ripening?
could you not have been ripening?
could they not have been ripening?