English verb conjugation
COULD MASS

Regular verb: mass - massed - massed

Affirmation

Simple form	V-ing form
I could mass you could mass he could mass we could mass you could mass they could mass	I could be massing you could be massing he could be massing we could be massing you could be massing they could be massing
Perfect	V-ing perfect
I could have massed you could have massed he could have massed we could have massed you could have massed they could have massed	I could have been massing you could have been massing he could have been massing we could have been massing you could have been massing they could have been massing

Negation

Simple form	V-ing form
I couldn't mass you couldn't mass he couldn't mass we couldn't mass you couldn't mass they couldn't mass	I couldn't be massing you couldn't be massing he couldn't be massing we couldn't be massing you couldn't be massing they couldn't be massing
Perfect	V-ing perfect
I couldn't have massed you couldn't have massed he couldn't have massed we couldn't have massed you couldn't have massed they couldn't have massed	I couldn't have been massing you couldn't have been massing he couldn't have been massing we couldn't have been massing you couldn't have been massing they couldn't have been massing

Interrogative form

Simple form	V-ing form
could I mass? could you mass? could he mass? could we mass? could you mass? could they mass?	could I be massing? could you be massing? could he be massing? could we be massing? could you be massing? could they be massing?
Perfect	V-ing perfect
could I have massed? could you have massed? could he have massed? could we have massed? could you have massed? could they have massed?	could I have been massing? could you have been massing? could he have been massing? could we have been massing? could you have been massing? could they have been massing?

Interro-negative form

Simple form	V-ing form
couldn't I mass? couldn't you mass? couldn't he mass? couldn't we mass? couldn't you mass? couldn't they mass?	couldn't I be massing? couldn't you be massing? couldn't he be massing? couldn't we be massing? couldn't you be massing? couldn't they be massing?
Perfect	V-ing perfect
couldn't I have massed? couldn't you have massed? couldn't he have massed? couldn't we have massed? couldn't you have massed? couldn't they have massed?	couldn't I have been massing? couldn't you have been massing? couldn't he have been massing? couldn't we have been massing? couldn't you have been massing? couldn't they have been massing?