could retrofit
Irregular verb: retrofit - retrofit- retrofit

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could retrofit
you could retrofit
he could retrofit
we could retrofit
you could retrofit
they could retrofit 	I could be retrofiting
you could be retrofiting
he could be retrofiting
we could be retrofiting
you could be retrofiting
they could be retrofiting	I could have retrofit
you could have retrofit
he could have retrofit
we could have retrofit
you could have retrofit
they could have retrofit	I could have been retrofiting
you could have been retrofiting
he could have been retrofiting
we could have been retrofiting
you could have been retrofiting
they could have been retrofiting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not retrofit
you could not retrofit
he could not retrofit
we could not retrofit
you could not retrofit
they could not retrofit 	I could not be retrofiting
you could not be retrofiting
he could not be retrofiting
we could not be retrofiting
you could not be retrofiting
they could not be retrofiting	I could not have retrofit
you could not have retrofit
he could not have retrofit
we could not have retrofit
you could not have retrofit
they could not have retrofit	I could not have been retrofiting
you could not have been retrofiting
he could not have been retrofiting
we could not have been retrofiting
you could not have been retrofiting
they could not have been retrofiting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I retrofit?
could you retrofit?
could he retrofit?
could we retrofit?
could you retrofit?
could they retrofit? 	could I be retrofiting?
could you be retrofiting?
could he be retrofiting?
could we be retrofiting?
could you be retrofiting?
could they be retrofiting? 	could I have retrofit?
could you have retrofit?
could he have retrofit?
could we have retrofit?
could you have retrofit?
could they have retrofit? 	could I have been retrofiting?
could you have been retrofiting?
could he have been retrofiting?
could we have been retrofiting?
could you have been retrofiting?
could they have been retrofiting? 	

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