could tun
Regular verb: tun - tuned- tuned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could tun
you could tun
she could tun
we could tun
you could tun
they could tun 	I could be tuning
you could be tuning
she could be tuning
we could be tuning
you could be tuning
they could be tuning	I could have tuned
you could have tuned
she could have tuned
we could have tuned
you could have tuned
they could have tuned	I could have been tuning
you could have been tuning
she could have been tuning
we could have been tuning
you could have been tuning
they could have been tuning	

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

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I tun?
could you tun?
could she tun?
could we tun?
could you tun?
could they tun? 	could I be tuning?
could you be tuning?
could she be tuning?
could we be tuning?
could you be tuning?
could they be tuning? 	could I have tuned?
could you have tuned?
could she have tuned?
could we have tuned?
could you have tuned?
could they have tuned? 	could I have been tuning?
could you have been tuning?
could she have been tuning?
could we have been tuning?
could you have been tuning?
could they have been tuning? 	

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