English verb conjugation
COULD GAS

Regular verb: gas - gassed - gassed

Affirmation

Simple form	V-ing form
I could gas you could gas he could gas we could gas you could gas they could gas	I could be gassing you could be gassing he could be gassing we could be gassing you could be gassing they could be gassing
Perfect	V-ing perfect
I could have gassed you could have gassed he could have gassed we could have gassed you could have gassed they could have gassed	I could have been gassing you could have been gassing he could have been gassing we could have been gassing you could have been gassing they could have been gassing

Negation

Simple form	V-ing form
I could not gas you could not gas he could not gas we could not gas you could not gas they could not gas	I could not be gassing you could not be gassing he could not be gassing we could not be gassing you could not be gassing they could not be gassing
Perfect	V-ing perfect
I could not have gassed you could not have gassed he could not have gassed we could not have gassed you could not have gassed they could not have gassed	I could not have been gassing you could not have been gassing he could not have been gassing we could not have been gassing you could not have been gassing they could not have been gassing

Interrogative form

Simple form	V-ing form
could I gas? could you gas? could he gas? could we gas? could you gas? could they gas?	could I be gassing? could you be gassing? could he be gassing? could we be gassing? could you be gassing? could they be gassing?
Perfect	V-ing perfect
could I have gassed? could you have gassed? could he have gassed? could we have gassed? could you have gassed? could they have gassed?	could I have been gassing? could you have been gassing? could he have been gassing? could we have been gassing? could you have been gassing? could they have been gassing?

Interro-negative form

Simple form	V-ing form
could I not gas? could you not gas? could he not gas? could we not gas? could you not gas? could they not gas?	could I not be gassing? could you not be gassing? could he not be gassing? could we not be gassing? could you not be gassing? could they not be gassing?
Perfect	V-ing perfect
could I not have gassed? could you not have gassed? could he not have gassed? could we not have gassed? could you not have gassed? could they not have gassed?	could I not have been gassing? could you not have been gassing? could he not have been gassing? could we not have been gassing? could you not have been gassing? could they not have been gassing?