could teleconference
Regular verb: teleconference - teleconferenced- teleconferenced

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could teleconference
you could teleconference
he could teleconference
we could teleconference
you could teleconference
they could teleconference 	I could be teleconferencing
you could be teleconferencing
he could be teleconferencing
we could be teleconferencing
you could be teleconferencing
they could be teleconferencing	I could have teleconferenced
you could have teleconferenced
he could have teleconferenced
we could have teleconferenced
you could have teleconferenced
they could have teleconferenced	I could have been teleconferencing
you could have been teleconferencing
he could have been teleconferencing
we could have been teleconferencing
you could have been teleconferencing
they could have been teleconferencing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't teleconference
you couldn't teleconference
he couldn't teleconference
we couldn't teleconference
you couldn't teleconference
they couldn't teleconference 	I couldn't be teleconferencing
you couldn't be teleconferencing
he couldn't be teleconferencing
we couldn't be teleconferencing
you couldn't be teleconferencing
they couldn't be teleconferencing	I couldn't have teleconferenced
you couldn't have teleconferenced
he couldn't have teleconferenced
we couldn't have teleconferenced
you couldn't have teleconferenced
they couldn't have teleconferenced	I couldn't have been teleconferencing
you couldn't have been teleconferencing
he couldn't have been teleconferencing
we couldn't have been teleconferencing
you couldn't have been teleconferencing
they couldn't have been teleconferencing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I teleconference?
could you teleconference?
could he teleconference?
could we teleconference?
could you teleconference?
could they teleconference? 	could I be teleconferencing?
could you be teleconferencing?
could he be teleconferencing?
could we be teleconferencing?
could you be teleconferencing?
could they be teleconferencing? 	could I have teleconferenced?
could you have teleconferenced?
could he have teleconferenced?
could we have teleconferenced?
could you have teleconferenced?
could they have teleconferenced? 	could I have been teleconferencing?
could you have been teleconferencing?
could he have been teleconferencing?
could we have been teleconferencing?
could you have been teleconferencing?
could they have been teleconferencing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I teleconference?
couldn't you teleconference?
couldn't he teleconference?
couldn't we teleconference?
couldn't you teleconference?
couldn't they teleconference? 	couldn't I be teleconferencing?
couldn't you be teleconferencing?
couldn't he be teleconferencing?
couldn't we be teleconferencing?
couldn't you be teleconferencing?
couldn't they be teleconferencing? 	couldn't I have teleconferenced?
couldn't you have teleconferenced?
couldn't he have teleconferenced?
couldn't we have teleconferenced?
couldn't you have teleconferenced?
couldn't they have teleconferenced? 	couldn't I have been teleconferencing?
couldn't you have been teleconferencing?
couldn't he have been teleconferencing?
couldn't we have been teleconferencing?
couldn't you have been teleconferencing?
couldn't they have been teleconferencing?