English verb conjugation
COULD ROOST

Regular verb: roost - roosted - roosted

Affirmation

Simple form	V-ing form
I could roost you could roost he could roost we could roost you could roost they could roost	I could be roosting you could be roosting he could be roosting we could be roosting you could be roosting they could be roosting
Perfect	V-ing perfect
I could have roosted you could have roosted he could have roosted we could have roosted you could have roosted they could have roosted	I could have been roosting you could have been roosting he could have been roosting we could have been roosting you could have been roosting they could have been roosting

Negation

Simple form	V-ing form
I couldn't roost you couldn't roost he couldn't roost we couldn't roost you couldn't roost they couldn't roost	I couldn't be roosting you couldn't be roosting he couldn't be roosting we couldn't be roosting you couldn't be roosting they couldn't be roosting
Perfect	V-ing perfect
I couldn't have roosted you couldn't have roosted he couldn't have roosted we couldn't have roosted you couldn't have roosted they couldn't have roosted	I couldn't have been roosting you couldn't have been roosting he couldn't have been roosting we couldn't have been roosting you couldn't have been roosting they couldn't have been roosting

Interrogative form

Simple form	V-ing form
could I roost? could you roost? could he roost? could we roost? could you roost? could they roost?	could I be roosting? could you be roosting? could he be roosting? could we be roosting? could you be roosting? could they be roosting?
Perfect	V-ing perfect
could I have roosted? could you have roosted? could he have roosted? could we have roosted? could you have roosted? could they have roosted?	could I have been roosting? could you have been roosting? could he have been roosting? could we have been roosting? could you have been roosting? could they have been roosting?

Interro-negative form

Simple form	V-ing form
couldn't I roost? couldn't you roost? couldn't he roost? couldn't we roost? couldn't you roost? couldn't they roost?	couldn't I be roosting? couldn't you be roosting? couldn't he be roosting? couldn't we be roosting? couldn't you be roosting? couldn't they be roosting?
Perfect	V-ing perfect
couldn't I have roosted? couldn't you have roosted? couldn't he have roosted? couldn't we have roosted? couldn't you have roosted? couldn't they have roosted?	couldn't I have been roosting? couldn't you have been roosting? couldn't he have been roosting? couldn't we have been roosting? couldn't you have been roosting? couldn't they have been roosting?