English verb conjugation
COULD GRASS

Regular verb: grass - grassed - grassed

Affirmation

Simple form	V-ing form
I could grass you could grass he could grass we could grass you could grass they could grass	I could be grassing you could be grassing he could be grassing we could be grassing you could be grassing they could be grassing
Perfect	V-ing perfect
I could have grassed you could have grassed he could have grassed we could have grassed you could have grassed they could have grassed	I could have been grassing you could have been grassing he could have been grassing we could have been grassing you could have been grassing they could have been grassing

Negation

Simple form	V-ing form
I couldn't grass you couldn't grass he couldn't grass we couldn't grass you couldn't grass they couldn't grass	I couldn't be grassing you couldn't be grassing he couldn't be grassing we couldn't be grassing you couldn't be grassing they couldn't be grassing
Perfect	V-ing perfect
I couldn't have grassed you couldn't have grassed he couldn't have grassed we couldn't have grassed you couldn't have grassed they couldn't have grassed	I couldn't have been grassing you couldn't have been grassing he couldn't have been grassing we couldn't have been grassing you couldn't have been grassing they couldn't have been grassing

Interrogative form

Simple form	V-ing form
could I grass? could you grass? could he grass? could we grass? could you grass? could they grass?	could I be grassing? could you be grassing? could he be grassing? could we be grassing? could you be grassing? could they be grassing?
Perfect	V-ing perfect
could I have grassed? could you have grassed? could he have grassed? could we have grassed? could you have grassed? could they have grassed?	could I have been grassing? could you have been grassing? could he have been grassing? could we have been grassing? could you have been grassing? could they have been grassing?

Interro-negative form

Simple form	V-ing form
couldn't I grass? couldn't you grass? couldn't he grass? couldn't we grass? couldn't you grass? couldn't they grass?	couldn't I be grassing? couldn't you be grassing? couldn't he be grassing? couldn't we be grassing? couldn't you be grassing? couldn't they be grassing?
Perfect	V-ing perfect
couldn't I have grassed? couldn't you have grassed? couldn't he have grassed? couldn't we have grassed? couldn't you have grassed? couldn't they have grassed?	couldn't I have been grassing? couldn't you have been grassing? couldn't he have been grassing? couldn't we have been grassing? couldn't you have been grassing? couldn't they have been grassing?