could interline
Regular verb: interline - interlined- interlined

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could interline
you could interline
she could interline
we could interline
you could interline
they could interline 	I could be interlining
you could be interlining
she could be interlining
we could be interlining
you could be interlining
they could be interlining	I could have interlined
you could have interlined
she could have interlined
we could have interlined
you could have interlined
they could have interlined	I could have been interlining
you could have been interlining
she could have been interlining
we could have been interlining
you could have been interlining
they could have been interlining	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't interline
you couldn't interline
she couldn't interline
we couldn't interline
you couldn't interline
they couldn't interline 	I couldn't be interlining
you couldn't be interlining
she couldn't be interlining
we couldn't be interlining
you couldn't be interlining
they couldn't be interlining	I couldn't have interlined
you couldn't have interlined
she couldn't have interlined
we couldn't have interlined
you couldn't have interlined
they couldn't have interlined	I couldn't have been interlining
you couldn't have been interlining
she couldn't have been interlining
we couldn't have been interlining
you couldn't have been interlining
they couldn't have been interlining	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I interline?
could you interline?
could she interline?
could we interline?
could you interline?
could they interline? 	could I be interlining?
could you be interlining?
could she be interlining?
could we be interlining?
could you be interlining?
could they be interlining? 	could I have interlined?
could you have interlined?
could she have interlined?
could we have interlined?
could you have interlined?
could they have interlined? 	could I have been interlining?
could you have been interlining?
could she have been interlining?
could we have been interlining?
could you have been interlining?
could they have been interlining? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I interline?
couldn't you interline?
couldn't she interline?
couldn't we interline?
couldn't you interline?
couldn't they interline? 	couldn't I be interlining?
couldn't you be interlining?
couldn't she be interlining?
couldn't we be interlining?
couldn't you be interlining?
couldn't they be interlining? 	couldn't I have interlined?
couldn't you have interlined?
couldn't she have interlined?
couldn't we have interlined?
couldn't you have interlined?
couldn't they have interlined? 	couldn't I have been interlining?
couldn't you have been interlining?
couldn't she have been interlining?
couldn't we have been interlining?
couldn't you have been interlining?
couldn't they have been interlining?