could interface
Regular verb: interface - interfaced- interfaced

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could interface
you could interface
she could interface
we could interface
you could interface
they could interface 	I could be interfacing
you could be interfacing
she could be interfacing
we could be interfacing
you could be interfacing
they could be interfacing	I could have interfaced
you could have interfaced
she could have interfaced
we could have interfaced
you could have interfaced
they could have interfaced	I could have been interfacing
you could have been interfacing
she could have been interfacing
we could have been interfacing
you could have been interfacing
they could have been interfacing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't interface
you couldn't interface
she couldn't interface
we couldn't interface
you couldn't interface
they couldn't interface 	I couldn't be interfacing
you couldn't be interfacing
she couldn't be interfacing
we couldn't be interfacing
you couldn't be interfacing
they couldn't be interfacing	I couldn't have interfaced
you couldn't have interfaced
she couldn't have interfaced
we couldn't have interfaced
you couldn't have interfaced
they couldn't have interfaced	I couldn't have been interfacing
you couldn't have been interfacing
she couldn't have been interfacing
we couldn't have been interfacing
you couldn't have been interfacing
they couldn't have been interfacing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I interface?
could you interface?
could she interface?
could we interface?
could you interface?
could they interface? 	could I be interfacing?
could you be interfacing?
could she be interfacing?
could we be interfacing?
could you be interfacing?
could they be interfacing? 	could I have interfaced?
could you have interfaced?
could she have interfaced?
could we have interfaced?
could you have interfaced?
could they have interfaced? 	could I have been interfacing?
could you have been interfacing?
could she have been interfacing?
could we have been interfacing?
could you have been interfacing?
could they have been interfacing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I interface?
couldn't you interface?
couldn't she interface?
couldn't we interface?
couldn't you interface?
couldn't they interface? 	couldn't I be interfacing?
couldn't you be interfacing?
couldn't she be interfacing?
couldn't we be interfacing?
couldn't you be interfacing?
couldn't they be interfacing? 	couldn't I have interfaced?
couldn't you have interfaced?
couldn't she have interfaced?
couldn't we have interfaced?
couldn't you have interfaced?
couldn't they have interfaced? 	couldn't I have been interfacing?
couldn't you have been interfacing?
couldn't she have been interfacing?
couldn't we have been interfacing?
couldn't you have been interfacing?
couldn't they have been interfacing?