I can board you can board he can board we can board you can board they can board
V-ing form
I can be boarding you can be boarding he can be boarding we can be boarding you can be boarding they can be boarding
Perfect
I can have boarded you can have boarded he can have boarded we can have boarded you can have boarded they can have boarded
V-ing perfect
I can have been boarding you can have been boarding he can have been boarding we can have been boarding you can have been boarding they can have been boarding
Negation
Simple form
I can't board you can't board he can't board we can't board you can't board they can't board
V-ing form
I can't be boarding you can't be boarding he can't be boarding we can't be boarding you can't be boarding they can't be boarding
Perfect
I can't have boarded you can't have boarded he can't have boarded we can't have boarded you can't have boarded they can't have boarded
V-ing perfect
I can't have been boarding you can't have been boarding he can't have been boarding we can't have been boarding you can't have been boarding they can't have been boarding
Interrogative form
Simple form
can I board? can you board? can he board? can we board? can you board? can they board?
V-ing form
can I be boarding? can you be boarding? can he be boarding? can we be boarding? can you be boarding? can they be boarding?
Perfect
can I have boarded? can you have boarded? can he have boarded? can we have boarded? can you have boarded? can they have boarded?
V-ing perfect
can I have been boarding? can you have been boarding? can he have been boarding? can we have been boarding? can you have been boarding? can they have been boarding?
Interro-negative form
Simple form
can't I board? can't you board? can't he board? can't we board? can't you board? can't they board?
V-ing form
can't I be boarding? can't you be boarding? can't he be boarding? can't we be boarding? can't you be boarding? can't they be boarding?
Perfect
can't I have boarded? can't you have boarded? can't he have boarded? can't we have boarded? can't you have boarded? can't they have boarded?
V-ing perfect
can't I have been boarding? can't you have been boarding? can't he have been boarding? can't we have been boarding? can't you have been boarding? can't they have been boarding?