English verb conjugation
COULD CENTRIFUGE

Regular verb: centrifuge - centrifuged - centrifuged

Affirmation

Simple form	V-ing form
I could centrifuge you could centrifuge he could centrifuge we could centrifuge you could centrifuge they could centrifuge	I could be centrifuging you could be centrifuging he could be centrifuging we could be centrifuging you could be centrifuging they could be centrifuging
Perfect	V-ing perfect
I could have centrifuged you could have centrifuged he could have centrifuged we could have centrifuged you could have centrifuged they could have centrifuged	I could have been centrifuging you could have been centrifuging he could have been centrifuging we could have been centrifuging you could have been centrifuging they could have been centrifuging

Negation

Simple form	V-ing form
I couldn't centrifuge you couldn't centrifuge he couldn't centrifuge we couldn't centrifuge you couldn't centrifuge they couldn't centrifuge	I couldn't be centrifuging you couldn't be centrifuging he couldn't be centrifuging we couldn't be centrifuging you couldn't be centrifuging they couldn't be centrifuging
Perfect	V-ing perfect
I couldn't have centrifuged you couldn't have centrifuged he couldn't have centrifuged we couldn't have centrifuged you couldn't have centrifuged they couldn't have centrifuged	I couldn't have been centrifuging you couldn't have been centrifuging he couldn't have been centrifuging we couldn't have been centrifuging you couldn't have been centrifuging they couldn't have been centrifuging

Interrogative form

Simple form	V-ing form
could I centrifuge? could you centrifuge? could he centrifuge? could we centrifuge? could you centrifuge? could they centrifuge?	could I be centrifuging? could you be centrifuging? could he be centrifuging? could we be centrifuging? could you be centrifuging? could they be centrifuging?
Perfect	V-ing perfect
could I have centrifuged? could you have centrifuged? could he have centrifuged? could we have centrifuged? could you have centrifuged? could they have centrifuged?	could I have been centrifuging? could you have been centrifuging? could he have been centrifuging? could we have been centrifuging? could you have been centrifuging? could they have been centrifuging?

Interro-negative form

Simple form	V-ing form
couldn't I centrifuge? couldn't you centrifuge? couldn't he centrifuge? couldn't we centrifuge? couldn't you centrifuge? couldn't they centrifuge?	couldn't I be centrifuging? couldn't you be centrifuging? couldn't he be centrifuging? couldn't we be centrifuging? couldn't you be centrifuging? couldn't they be centrifuging?
Perfect	V-ing perfect
couldn't I have centrifuged? couldn't you have centrifuged? couldn't he have centrifuged? couldn't we have centrifuged? couldn't you have centrifuged? couldn't they have centrifuged?	couldn't I have been centrifuging? couldn't you have been centrifuging? couldn't he have been centrifuging? couldn't we have been centrifuging? couldn't you have been centrifuging? couldn't they have been centrifuging?