I can crab you can crab he can crab we can crab you can crab they can crab
V-ing form
I can be crabbing you can be crabbing he can be crabbing we can be crabbing you can be crabbing they can be crabbing
Perfect
I can have crabbed you can have crabbed he can have crabbed we can have crabbed you can have crabbed they can have crabbed
V-ing perfect
I can have been crabbing you can have been crabbing he can have been crabbing we can have been crabbing you can have been crabbing they can have been crabbing
Negation
Simple form
I cannot crab you cannot crab he cannot crab we cannot crab you cannot crab they cannot crab
V-ing form
I cannot be crabbing you cannot be crabbing he cannot be crabbing we cannot be crabbing you cannot be crabbing they cannot be crabbing
Perfect
I cannot have crabbed you cannot have crabbed he cannot have crabbed we cannot have crabbed you cannot have crabbed they cannot have crabbed
V-ing perfect
I cannot have been crabbing you cannot have been crabbing he cannot have been crabbing we cannot have been crabbing you cannot have been crabbing they cannot have been crabbing
Interrogative form
Simple form
can I crab? can you crab? can he crab? can we crab? can you crab? can they crab?
V-ing form
can I be crabbing? can you be crabbing? can he be crabbing? can we be crabbing? can you be crabbing? can they be crabbing?
Perfect
can I have crabbed? can you have crabbed? can he have crabbed? can we have crabbed? can you have crabbed? can they have crabbed?
V-ing perfect
can I have been crabbing? can you have been crabbing? can he have been crabbing? can we have been crabbing? can you have been crabbing? can they have been crabbing?
Interro-negative form
Simple form
can I not crab? can you not crab? can he not crab? can we not crab? can you not crab? can they not crab?
V-ing form
can I not be crabbing? can you not be crabbing? can he not be crabbing? can we not be crabbing? can you not be crabbing? can they not be crabbing?
Perfect
can I not have crabbed? can you not have crabbed? can he not have crabbed? can we not have crabbed? can you not have crabbed? can they not have crabbed?
V-ing perfect
can I not have been crabbing? can you not have been crabbing? can he not have been crabbing? can we not have been crabbing? can you not have been crabbing? can they not have been crabbing?