English verb conjugation
COULD FILL

Regular verb: fill - filled - filled

Affirmation

Simple form	V-ing form
I could fill you could fill he could fill we could fill you could fill they could fill	I could be filling you could be filling he could be filling we could be filling you could be filling they could be filling
Perfect	V-ing perfect
I could have filled you could have filled he could have filled we could have filled you could have filled they could have filled	I could have been filling you could have been filling he could have been filling we could have been filling you could have been filling they could have been filling

Negation

Simple form	V-ing form
I couldn't fill you couldn't fill he couldn't fill we couldn't fill you couldn't fill they couldn't fill	I couldn't be filling you couldn't be filling he couldn't be filling we couldn't be filling you couldn't be filling they couldn't be filling
Perfect	V-ing perfect
I couldn't have filled you couldn't have filled he couldn't have filled we couldn't have filled you couldn't have filled they couldn't have filled	I couldn't have been filling you couldn't have been filling he couldn't have been filling we couldn't have been filling you couldn't have been filling they couldn't have been filling

Interrogative form

Simple form	V-ing form
could I fill? could you fill? could he fill? could we fill? could you fill? could they fill?	could I be filling? could you be filling? could he be filling? could we be filling? could you be filling? could they be filling?
Perfect	V-ing perfect
could I have filled? could you have filled? could he have filled? could we have filled? could you have filled? could they have filled?	could I have been filling? could you have been filling? could he have been filling? could we have been filling? could you have been filling? could they have been filling?

Interro-negative form

Simple form	V-ing form
couldn't I fill? couldn't you fill? couldn't he fill? couldn't we fill? couldn't you fill? couldn't they fill?	couldn't I be filling? couldn't you be filling? couldn't he be filling? couldn't we be filling? couldn't you be filling? couldn't they be filling?
Perfect	V-ing perfect
couldn't I have filled? couldn't you have filled? couldn't he have filled? couldn't we have filled? couldn't you have filled? couldn't they have filled?	couldn't I have been filling? couldn't you have been filling? couldn't he have been filling? couldn't we have been filling? couldn't you have been filling? couldn't they have been filling?