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 could not mass you could not mass he could not mass we could not mass you could not mass they could not mass	I could not be massing you could not be massing he could not be massing we could not be massing you could not be massing they could not be massing
Perfect	V-ing perfect
I could not have massed you could not have massed he could not have massed we could not have massed you could not have massed they could not have massed	I could not have been massing you could not have been massing he could not have been massing we could not have been massing you could not have been massing they could not 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
could I not mass? could you not mass? could he not mass? could we not mass? could you not mass? could they not mass?	could I not be massing? could you not be massing? could he not be massing? could we not be massing? could you not be massing? could they not be massing?
Perfect	V-ing perfect
could I not have massed? could you not have massed? could he not have massed? could we not have massed? could you not have massed? could they not have massed?	could I not have been massing? could you not have been massing? could he not have been massing? could we not have been massing? could you not have been massing? could they not have been massing?