English verb conjugation
COULD WHIRR

Regular verb: whirr - whirred - whirred

Affirmation

Simple form	V-ing form
I could whirr you could whirr he could whirr we could whirr you could whirr they could whirr	I could be whirring you could be whirring he could be whirring we could be whirring you could be whirring they could be whirring
Perfect	V-ing perfect
I could have whirred you could have whirred he could have whirred we could have whirred you could have whirred they could have whirred	I could have been whirring you could have been whirring he could have been whirring we could have been whirring you could have been whirring they could have been whirring

Negation

Simple form	V-ing form
I couldn't whirr you couldn't whirr he couldn't whirr we couldn't whirr you couldn't whirr they couldn't whirr	I couldn't be whirring you couldn't be whirring he couldn't be whirring we couldn't be whirring you couldn't be whirring they couldn't be whirring
Perfect	V-ing perfect
I couldn't have whirred you couldn't have whirred he couldn't have whirred we couldn't have whirred you couldn't have whirred they couldn't have whirred	I couldn't have been whirring you couldn't have been whirring he couldn't have been whirring we couldn't have been whirring you couldn't have been whirring they couldn't have been whirring

Interrogative form

Simple form	V-ing form
could I whirr? could you whirr? could he whirr? could we whirr? could you whirr? could they whirr?	could I be whirring? could you be whirring? could he be whirring? could we be whirring? could you be whirring? could they be whirring?
Perfect	V-ing perfect
could I have whirred? could you have whirred? could he have whirred? could we have whirred? could you have whirred? could they have whirred?	could I have been whirring? could you have been whirring? could he have been whirring? could we have been whirring? could you have been whirring? could they have been whirring?

Interro-negative form

Simple form	V-ing form
couldn't I whirr? couldn't you whirr? couldn't he whirr? couldn't we whirr? couldn't you whirr? couldn't they whirr?	couldn't I be whirring? couldn't you be whirring? couldn't he be whirring? couldn't we be whirring? couldn't you be whirring? couldn't they be whirring?
Perfect	V-ing perfect
couldn't I have whirred? couldn't you have whirred? couldn't he have whirred? couldn't we have whirred? couldn't you have whirred? couldn't they have whirred?	couldn't I have been whirring? couldn't you have been whirring? couldn't he have been whirring? couldn't we have been whirring? couldn't you have been whirring? couldn't they have been whirring?