could naturalise
Regular verb: naturalise - naturalised- naturalised

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could naturalise
you could naturalise
he could naturalise
we could naturalise
you could naturalise
they could naturalise 	I could be naturalising
you could be naturalising
he could be naturalising
we could be naturalising
you could be naturalising
they could be naturalising	I could have naturalised
you could have naturalised
he could have naturalised
we could have naturalised
you could have naturalised
they could have naturalised	I could have been naturalising
you could have been naturalising
he could have been naturalising
we could have been naturalising
you could have been naturalising
they could have been naturalising	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't naturalise
you couldn't naturalise
he couldn't naturalise
we couldn't naturalise
you couldn't naturalise
they couldn't naturalise 	I couldn't be naturalising
you couldn't be naturalising
he couldn't be naturalising
we couldn't be naturalising
you couldn't be naturalising
they couldn't be naturalising	I couldn't have naturalised
you couldn't have naturalised
he couldn't have naturalised
we couldn't have naturalised
you couldn't have naturalised
they couldn't have naturalised	I couldn't have been naturalising
you couldn't have been naturalising
he couldn't have been naturalising
we couldn't have been naturalising
you couldn't have been naturalising
they couldn't have been naturalising	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I naturalise?
could you naturalise?
could he naturalise?
could we naturalise?
could you naturalise?
could they naturalise? 	could I be naturalising?
could you be naturalising?
could he be naturalising?
could we be naturalising?
could you be naturalising?
could they be naturalising? 	could I have naturalised?
could you have naturalised?
could he have naturalised?
could we have naturalised?
could you have naturalised?
could they have naturalised? 	could I have been naturalising?
could you have been naturalising?
could he have been naturalising?
could we have been naturalising?
could you have been naturalising?
could they have been naturalising? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I naturalise?
couldn't you naturalise?
couldn't he naturalise?
couldn't we naturalise?
couldn't you naturalise?
couldn't they naturalise? 	couldn't I be naturalising?
couldn't you be naturalising?
couldn't he be naturalising?
couldn't we be naturalising?
couldn't you be naturalising?
couldn't they be naturalising? 	couldn't I have naturalised?
couldn't you have naturalised?
couldn't he have naturalised?
couldn't we have naturalised?
couldn't you have naturalised?
couldn't they have naturalised? 	couldn't I have been naturalising?
couldn't you have been naturalising?
couldn't he have been naturalising?
couldn't we have been naturalising?
couldn't you have been naturalising?
couldn't they have been naturalising?