I can flash you can flash he can flash we can flash you can flash they can flash
V-ing form
I can be flashing you can be flashing he can be flashing we can be flashing you can be flashing they can be flashing
Perfect
I can have flashed you can have flashed he can have flashed we can have flashed you can have flashed they can have flashed
V-ing perfect
I can have been flashing you can have been flashing he can have been flashing we can have been flashing you can have been flashing they can have been flashing
Negation
Simple form
I can't flash you can't flash he can't flash we can't flash you can't flash they can't flash
V-ing form
I can't be flashing you can't be flashing he can't be flashing we can't be flashing you can't be flashing they can't be flashing
Perfect
I can't have flashed you can't have flashed he can't have flashed we can't have flashed you can't have flashed they can't have flashed
V-ing perfect
I can't have been flashing you can't have been flashing he can't have been flashing we can't have been flashing you can't have been flashing they can't have been flashing
Interrogative form
Simple form
can I flash? can you flash? can he flash? can we flash? can you flash? can they flash?
V-ing form
can I be flashing? can you be flashing? can he be flashing? can we be flashing? can you be flashing? can they be flashing?
Perfect
can I have flashed? can you have flashed? can he have flashed? can we have flashed? can you have flashed? can they have flashed?
V-ing perfect
can I have been flashing? can you have been flashing? can he have been flashing? can we have been flashing? can you have been flashing? can they have been flashing?
Interro-negative form
Simple form
can't I flash? can't you flash? can't he flash? can't we flash? can't you flash? can't they flash?
V-ing form
can't I be flashing? can't you be flashing? can't he be flashing? can't we be flashing? can't you be flashing? can't they be flashing?
Perfect
can't I have flashed? can't you have flashed? can't he have flashed? can't we have flashed? can't you have flashed? can't they have flashed?
V-ing perfect
can't I have been flashing? can't you have been flashing? can't he have been flashing? can't we have been flashing? can't you have been flashing? can't they have been flashing?