could turn
Regular verb: turn - turned- turned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could turn
you could turn
he could turn
we could turn
you could turn
they could turn 	I could be turning
you could be turning
he could be turning
we could be turning
you could be turning
they could be turning	I could have turned
you could have turned
he could have turned
we could have turned
you could have turned
they could have turned	I could have been turning
you could have been turning
he could have been turning
we could have been turning
you could have been turning
they could have been turning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't turn
you couldn't turn
he couldn't turn
we couldn't turn
you couldn't turn
they couldn't turn 	I couldn't be turning
you couldn't be turning
he couldn't be turning
we couldn't be turning
you couldn't be turning
they couldn't be turning	I couldn't have turned
you couldn't have turned
he couldn't have turned
we couldn't have turned
you couldn't have turned
they couldn't have turned	I couldn't have been turning
you couldn't have been turning
he couldn't have been turning
we couldn't have been turning
you couldn't have been turning
they couldn't have been turning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I turn?
could you turn?
could he turn?
could we turn?
could you turn?
could they turn? 	could I be turning?
could you be turning?
could he be turning?
could we be turning?
could you be turning?
could they be turning? 	could I have turned?
could you have turned?
could he have turned?
could we have turned?
could you have turned?
could they have turned? 	could I have been turning?
could you have been turning?
could he have been turning?
could we have been turning?
could you have been turning?
could they have been turning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I turn?
couldn't you turn?
couldn't he turn?
couldn't we turn?
couldn't you turn?
couldn't they turn? 	couldn't I be turning?
couldn't you be turning?
couldn't he be turning?
couldn't we be turning?
couldn't you be turning?
couldn't they be turning? 	couldn't I have turned?
couldn't you have turned?
couldn't he have turned?
couldn't we have turned?
couldn't you have turned?
couldn't they have turned? 	couldn't I have been turning?
couldn't you have been turning?
couldn't he have been turning?
couldn't we have been turning?
couldn't you have been turning?
couldn't they have been turning?