English verb conjugation
COULD FLASH

Regular verb: flash - flashed - flashed

Affirmation

Simple form	V-ing form
I could flash you could flash he could flash we could flash you could flash they could flash	I could be flashing you could be flashing he could be flashing we could be flashing you could be flashing they could be flashing
Perfect	V-ing perfect
I could have flashed you could have flashed he could have flashed we could have flashed you could have flashed they could have flashed	I could have been flashing you could have been flashing he could have been flashing we could have been flashing you could have been flashing they could have been flashing

Negation

Simple form	V-ing form
I could not flash you could not flash he could not flash we could not flash you could not flash they could not flash	I could not be flashing you could not be flashing he could not be flashing we could not be flashing you could not be flashing they could not be flashing
Perfect	V-ing perfect
I could not have flashed you could not have flashed he could not have flashed we could not have flashed you could not have flashed they could not have flashed	I could not have been flashing you could not have been flashing he could not have been flashing we could not have been flashing you could not have been flashing they could not have been flashing

Interrogative form

Simple form	V-ing form
could I flash? could you flash? could he flash? could we flash? could you flash? could they flash?	could I be flashing? could you be flashing? could he be flashing? could we be flashing? could you be flashing? could they be flashing?
Perfect	V-ing perfect
could I have flashed? could you have flashed? could he have flashed? could we have flashed? could you have flashed? could they have flashed?	could I have been flashing? could you have been flashing? could he have been flashing? could we have been flashing? could you have been flashing? could they have been flashing?

Interro-negative form

Simple form	V-ing form
could I not flash? could you not flash? could he not flash? could we not flash? could you not flash? could they not flash?	could I not be flashing? could you not be flashing? could he not be flashing? could we not be flashing? could you not be flashing? could they not be flashing?
Perfect	V-ing perfect
could I not have flashed? could you not have flashed? could he not have flashed? could we not have flashed? could you not have flashed? could they not have flashed?	could I not have been flashing? could you not have been flashing? could he not have been flashing? could we not have been flashing? could you not have been flashing? could they not have been flashing?