could ultracentrifuge
Regular verb: ultracentrifuge - ultracentrifuged- ultracentrifuged

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could ultracentrifuge
you could ultracentrifuge
he could ultracentrifuge
we could ultracentrifuge
you could ultracentrifuge
they could ultracentrifuge 	I could be ultracentrifuging
you could be ultracentrifuging
he could be ultracentrifuging
we could be ultracentrifuging
you could be ultracentrifuging
they could be ultracentrifuging	I could have ultracentrifuged
you could have ultracentrifuged
he could have ultracentrifuged
we could have ultracentrifuged
you could have ultracentrifuged
they could have ultracentrifuged	I could have been ultracentrifuging
you could have been ultracentrifuging
he could have been ultracentrifuging
we could have been ultracentrifuging
you could have been ultracentrifuging
they could have been ultracentrifuging	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't ultracentrifuge
you couldn't ultracentrifuge
he couldn't ultracentrifuge
we couldn't ultracentrifuge
you couldn't ultracentrifuge
they couldn't ultracentrifuge 	I couldn't be ultracentrifuging
you couldn't be ultracentrifuging
he couldn't be ultracentrifuging
we couldn't be ultracentrifuging
you couldn't be ultracentrifuging
they couldn't be ultracentrifuging	I couldn't have ultracentrifuged
you couldn't have ultracentrifuged
he couldn't have ultracentrifuged
we couldn't have ultracentrifuged
you couldn't have ultracentrifuged
they couldn't have ultracentrifuged	I couldn't have been ultracentrifuging
you couldn't have been ultracentrifuging
he couldn't have been ultracentrifuging
we couldn't have been ultracentrifuging
you couldn't have been ultracentrifuging
they couldn't have been ultracentrifuging	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I ultracentrifuge?
could you ultracentrifuge?
could he ultracentrifuge?
could we ultracentrifuge?
could you ultracentrifuge?
could they ultracentrifuge? 	could I be ultracentrifuging?
could you be ultracentrifuging?
could he be ultracentrifuging?
could we be ultracentrifuging?
could you be ultracentrifuging?
could they be ultracentrifuging? 	could I have ultracentrifuged?
could you have ultracentrifuged?
could he have ultracentrifuged?
could we have ultracentrifuged?
could you have ultracentrifuged?
could they have ultracentrifuged? 	could I have been ultracentrifuging?
could you have been ultracentrifuging?
could he have been ultracentrifuging?
could we have been ultracentrifuging?
could you have been ultracentrifuging?
could they have been ultracentrifuging? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I ultracentrifuge?
couldn't you ultracentrifuge?
couldn't he ultracentrifuge?
couldn't we ultracentrifuge?
couldn't you ultracentrifuge?
couldn't they ultracentrifuge? 	couldn't I be ultracentrifuging?
couldn't you be ultracentrifuging?
couldn't he be ultracentrifuging?
couldn't we be ultracentrifuging?
couldn't you be ultracentrifuging?
couldn't they be ultracentrifuging? 	couldn't I have ultracentrifuged?
couldn't you have ultracentrifuged?
couldn't he have ultracentrifuged?
couldn't we have ultracentrifuged?
couldn't you have ultracentrifuged?
couldn't they have ultracentrifuged? 	couldn't I have been ultracentrifuging?
couldn't you have been ultracentrifuging?
couldn't he have been ultracentrifuging?
couldn't we have been ultracentrifuging?
couldn't you have been ultracentrifuging?
couldn't they have been ultracentrifuging?