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 couldn't flash you couldn't flash he couldn't flash we couldn't flash you couldn't flash they couldn't flash	I couldn't be flashing you couldn't be flashing he couldn't be flashing we couldn't be flashing you couldn't be flashing they couldn't be flashing
Perfect	V-ing perfect
I couldn't have flashed you couldn't have flashed he couldn't have flashed we couldn't have flashed you couldn't have flashed they couldn't have flashed	I couldn't have been flashing you couldn't have been flashing he couldn't have been flashing we couldn't have been flashing you couldn't have been flashing they couldn't 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
couldn't I flash? couldn't you flash? couldn't he flash? couldn't we flash? couldn't you flash? couldn't they flash?	couldn't I be flashing? couldn't you be flashing? couldn't he be flashing? couldn't we be flashing? couldn't you be flashing? couldn't they be flashing?
Perfect	V-ing perfect
couldn't I have flashed? couldn't you have flashed? couldn't he have flashed? couldn't we have flashed? couldn't you have flashed? couldn't they have flashed?	couldn't I have been flashing? couldn't you have been flashing? couldn't he have been flashing? couldn't we have been flashing? couldn't you have been flashing? couldn't they have been flashing?