could board
Regular verb: board - boarded- boarded

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
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	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 	Perfect 	V-ing perfect 	
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	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 	Perfect 	V-ing perfect 	
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? 	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 	Perfect 	V-ing perfect 	
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? 	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?