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 can't crab you can't crab he can't crab we can't crab you can't crab they can't crab
V-ing form
I can't be crabbing you can't be crabbing he can't be crabbing we can't be crabbing you can't be crabbing they can't be crabbing
Perfect
I can't have crabbed you can't have crabbed he can't have crabbed we can't have crabbed you can't have crabbed they can't have crabbed
V-ing perfect
I can't have been crabbing you can't have been crabbing he can't have been crabbing we can't have been crabbing you can't have been crabbing they can't 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't I crab? can't you crab? can't he crab? can't we crab? can't you crab? can't they crab?
V-ing form
can't I be crabbing? can't you be crabbing? can't he be crabbing? can't we be crabbing? can't you be crabbing? can't they be crabbing?
Perfect
can't I have crabbed? can't you have crabbed? can't he have crabbed? can't we have crabbed? can't you have crabbed? can't they have crabbed?
V-ing perfect
can't I have been crabbing? can't you have been crabbing? can't he have been crabbing? can't we have been crabbing? can't you have been crabbing? can't they have been crabbing?