English verb conjugation
COULD BOARD

Regular verb: board - boarded - boarded

Affirmation

Simple form	V-ing form
I could board you could board he could board we could board you could board they could board	I could be boarding you could be boarding he could be boarding we could be boarding you could be boarding they could be boarding
Perfect	V-ing perfect
I could have boarded you could have boarded he could have boarded we could have boarded you could have boarded they could have boarded	I could have been boarding you could have been boarding he could have been boarding we could have been boarding you could have been boarding they could have been boarding

Negation

Simple form	V-ing form
I could not board you could not board he could not board we could not board you could not board they could not board	I could not be boarding you could not be boarding he could not be boarding we could not be boarding you could not be boarding they could not be boarding
Perfect	V-ing perfect
I could not have boarded you could not have boarded he could not have boarded we could not have boarded you could not have boarded they could not have boarded	I could not have been boarding you could not have been boarding he could not have been boarding we could not have been boarding you could not have been boarding they could not have been boarding

Interrogative form

Simple form	V-ing form
could I board? could you board? could he board? could we board? could you board? could they board?	could I be boarding? could you be boarding? could he be boarding? could we be boarding? could you be boarding? could they be boarding?
Perfect	V-ing perfect
could I have boarded? could you have boarded? could he have boarded? could we have boarded? could you have boarded? could they have boarded?	could I have been boarding? could you have been boarding? could he have been boarding? could we have been boarding? could you have been boarding? could they have been boarding?

Interro-negative form

Simple form	V-ing form
could I not board? could you not board? could he not board? could we not board? could you not board? could they not board?	could I not be boarding? could you not be boarding? could he not be boarding? could we not be boarding? could you not be boarding? could they not be boarding?
Perfect	V-ing perfect
could I not have boarded? could you not have boarded? could he not have boarded? could we not have boarded? could you not have boarded? could they not have boarded?	could I not have been boarding? could you not have been boarding? could he not have been boarding? could we not have been boarding? could you not have been boarding? could they not have been boarding?