could crust
Regular verb: crust - crusted- crusted

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could crust
you could crust
she could crust
we could crust
you could crust
they could crust 	I could be crusting
you could be crusting
she could be crusting
we could be crusting
you could be crusting
they could be crusting	I could have crusted
you could have crusted
she could have crusted
we could have crusted
you could have crusted
they could have crusted	I could have been crusting
you could have been crusting
she could have been crusting
we could have been crusting
you could have been crusting
they could have been crusting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not crust
you could not crust
she could not crust
we could not crust
you could not crust
they could not crust 	I could not be crusting
you could not be crusting
she could not be crusting
we could not be crusting
you could not be crusting
they could not be crusting	I could not have crusted
you could not have crusted
she could not have crusted
we could not have crusted
you could not have crusted
they could not have crusted	I could not have been crusting
you could not have been crusting
she could not have been crusting
we could not have been crusting
you could not have been crusting
they could not have been crusting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I crust?
could you crust?
could she crust?
could we crust?
could you crust?
could they crust? 	could I be crusting?
could you be crusting?
could she be crusting?
could we be crusting?
could you be crusting?
could they be crusting? 	could I have crusted?
could you have crusted?
could she have crusted?
could we have crusted?
could you have crusted?
could they have crusted? 	could I have been crusting?
could you have been crusting?
could she have been crusting?
could we have been crusting?
could you have been crusting?
could they have been crusting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not crust?
could you not crust?
could she not crust?
could we not crust?
could you not crust?
could they not crust? 	could I not be crusting?
could you not be crusting?
could she not be crusting?
could we not be crusting?
could you not be crusting?
could they not be crusting? 	could I not have crusted?
could you not have crusted?
could she not have crusted?
could we not have crusted?
could you not have crusted?
could they not have crusted? 	could I not have been crusting?
could you not have been crusting?
could she not have been crusting?
could we not have been crusting?
could you not have been crusting?
could they not have been crusting?