could subtitle
Regular verb: subtitle - subtitled- subtitled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could subtitle
you could subtitle
he could subtitle
we could subtitle
you could subtitle
they could subtitle 	I could be subtitling
you could be subtitling
he could be subtitling
we could be subtitling
you could be subtitling
they could be subtitling	I could have subtitled
you could have subtitled
he could have subtitled
we could have subtitled
you could have subtitled
they could have subtitled	I could have been subtitling
you could have been subtitling
he could have been subtitling
we could have been subtitling
you could have been subtitling
they could have been subtitling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't subtitle
you couldn't subtitle
he couldn't subtitle
we couldn't subtitle
you couldn't subtitle
they couldn't subtitle 	I couldn't be subtitling
you couldn't be subtitling
he couldn't be subtitling
we couldn't be subtitling
you couldn't be subtitling
they couldn't be subtitling	I couldn't have subtitled
you couldn't have subtitled
he couldn't have subtitled
we couldn't have subtitled
you couldn't have subtitled
they couldn't have subtitled	I couldn't have been subtitling
you couldn't have been subtitling
he couldn't have been subtitling
we couldn't have been subtitling
you couldn't have been subtitling
they couldn't have been subtitling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I subtitle?
could you subtitle?
could he subtitle?
could we subtitle?
could you subtitle?
could they subtitle? 	could I be subtitling?
could you be subtitling?
could he be subtitling?
could we be subtitling?
could you be subtitling?
could they be subtitling? 	could I have subtitled?
could you have subtitled?
could he have subtitled?
could we have subtitled?
could you have subtitled?
could they have subtitled? 	could I have been subtitling?
could you have been subtitling?
could he have been subtitling?
could we have been subtitling?
could you have been subtitling?
could they have been subtitling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I subtitle?
couldn't you subtitle?
couldn't he subtitle?
couldn't we subtitle?
couldn't you subtitle?
couldn't they subtitle? 	couldn't I be subtitling?
couldn't you be subtitling?
couldn't he be subtitling?
couldn't we be subtitling?
couldn't you be subtitling?
couldn't they be subtitling? 	couldn't I have subtitled?
couldn't you have subtitled?
couldn't he have subtitled?
couldn't we have subtitled?
couldn't you have subtitled?
couldn't they have subtitled? 	couldn't I have been subtitling?
couldn't you have been subtitling?
couldn't he have been subtitling?
couldn't we have been subtitling?
couldn't you have been subtitling?
couldn't they have been subtitling?