could fine-tune
Regular verb: fine-tune - fine-tuned- fine-tuned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could fine-tune
you could fine-tune
he could fine-tune
we could fine-tune
you could fine-tune
they could fine-tune 	I could be fine-tuning
you could be fine-tuning
he could be fine-tuning
we could be fine-tuning
you could be fine-tuning
they could be fine-tuning	I could have fine-tuned
you could have fine-tuned
he could have fine-tuned
we could have fine-tuned
you could have fine-tuned
they could have fine-tuned	I could have been fine-tuning
you could have been fine-tuning
he could have been fine-tuning
we could have been fine-tuning
you could have been fine-tuning
they could have been fine-tuning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't fine-tune
you couldn't fine-tune
he couldn't fine-tune
we couldn't fine-tune
you couldn't fine-tune
they couldn't fine-tune 	I couldn't be fine-tuning
you couldn't be fine-tuning
he couldn't be fine-tuning
we couldn't be fine-tuning
you couldn't be fine-tuning
they couldn't be fine-tuning	I couldn't have fine-tuned
you couldn't have fine-tuned
he couldn't have fine-tuned
we couldn't have fine-tuned
you couldn't have fine-tuned
they couldn't have fine-tuned	I couldn't have been fine-tuning
you couldn't have been fine-tuning
he couldn't have been fine-tuning
we couldn't have been fine-tuning
you couldn't have been fine-tuning
they couldn't have been fine-tuning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I fine-tune?
could you fine-tune?
could he fine-tune?
could we fine-tune?
could you fine-tune?
could they fine-tune? 	could I be fine-tuning?
could you be fine-tuning?
could he be fine-tuning?
could we be fine-tuning?
could you be fine-tuning?
could they be fine-tuning? 	could I have fine-tuned?
could you have fine-tuned?
could he have fine-tuned?
could we have fine-tuned?
could you have fine-tuned?
could they have fine-tuned? 	could I have been fine-tuning?
could you have been fine-tuning?
could he have been fine-tuning?
could we have been fine-tuning?
could you have been fine-tuning?
could they have been fine-tuning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I fine-tune?
couldn't you fine-tune?
couldn't he fine-tune?
couldn't we fine-tune?
couldn't you fine-tune?
couldn't they fine-tune? 	couldn't I be fine-tuning?
couldn't you be fine-tuning?
couldn't he be fine-tuning?
couldn't we be fine-tuning?
couldn't you be fine-tuning?
couldn't they be fine-tuning? 	couldn't I have fine-tuned?
couldn't you have fine-tuned?
couldn't he have fine-tuned?
couldn't we have fine-tuned?
couldn't you have fine-tuned?
couldn't they have fine-tuned? 	couldn't I have been fine-tuning?
couldn't you have been fine-tuning?
couldn't he have been fine-tuning?
couldn't we have been fine-tuning?
couldn't you have been fine-tuning?
couldn't they have been fine-tuning?