could fret
Regular verb: fret - fretted- fretted

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could fret
you could fret
he could fret
we could fret
you could fret
they could fret 	I could be fretting
you could be fretting
he could be fretting
we could be fretting
you could be fretting
they could be fretting	I could have fretted
you could have fretted
he could have fretted
we could have fretted
you could have fretted
they could have fretted	I could have been fretting
you could have been fretting
he could have been fretting
we could have been fretting
you could have been fretting
they could have been fretting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't fret
you couldn't fret
he couldn't fret
we couldn't fret
you couldn't fret
they couldn't fret 	I couldn't be fretting
you couldn't be fretting
he couldn't be fretting
we couldn't be fretting
you couldn't be fretting
they couldn't be fretting	I couldn't have fretted
you couldn't have fretted
he couldn't have fretted
we couldn't have fretted
you couldn't have fretted
they couldn't have fretted	I couldn't have been fretting
you couldn't have been fretting
he couldn't have been fretting
we couldn't have been fretting
you couldn't have been fretting
they couldn't have been fretting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I fret?
could you fret?
could he fret?
could we fret?
could you fret?
could they fret? 	could I be fretting?
could you be fretting?
could he be fretting?
could we be fretting?
could you be fretting?
could they be fretting? 	could I have fretted?
could you have fretted?
could he have fretted?
could we have fretted?
could you have fretted?
could they have fretted? 	could I have been fretting?
could you have been fretting?
could he have been fretting?
could we have been fretting?
could you have been fretting?
could they have been fretting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I fret?
couldn't you fret?
couldn't he fret?
couldn't we fret?
couldn't you fret?
couldn't they fret? 	couldn't I be fretting?
couldn't you be fretting?
couldn't he be fretting?
couldn't we be fretting?
couldn't you be fretting?
couldn't they be fretting? 	couldn't I have fretted?
couldn't you have fretted?
couldn't he have fretted?
couldn't we have fretted?
couldn't you have fretted?
couldn't they have fretted? 	couldn't I have been fretting?
couldn't you have been fretting?
couldn't he have been fretting?
couldn't we have been fretting?
couldn't you have been fretting?
couldn't they have been fretting?