I can tumble you can tumble he can tumble we can tumble you can tumble they can tumble
V-ing form
I can be tumbling you can be tumbling he can be tumbling we can be tumbling you can be tumbling they can be tumbling
Perfect
I can have tumbled you can have tumbled he can have tumbled we can have tumbled you can have tumbled they can have tumbled
V-ing perfect
I can have been tumbling you can have been tumbling he can have been tumbling we can have been tumbling you can have been tumbling they can have been tumbling
Negation
Simple form
I can't tumble you can't tumble he can't tumble we can't tumble you can't tumble they can't tumble
V-ing form
I can't be tumbling you can't be tumbling he can't be tumbling we can't be tumbling you can't be tumbling they can't be tumbling
Perfect
I can't have tumbled you can't have tumbled he can't have tumbled we can't have tumbled you can't have tumbled they can't have tumbled
V-ing perfect
I can't have been tumbling you can't have been tumbling he can't have been tumbling we can't have been tumbling you can't have been tumbling they can't have been tumbling
Interrogative form
Simple form
can I tumble? can you tumble? can he tumble? can we tumble? can you tumble? can they tumble?
V-ing form
can I be tumbling? can you be tumbling? can he be tumbling? can we be tumbling? can you be tumbling? can they be tumbling?
Perfect
can I have tumbled? can you have tumbled? can he have tumbled? can we have tumbled? can you have tumbled? can they have tumbled?
V-ing perfect
can I have been tumbling? can you have been tumbling? can he have been tumbling? can we have been tumbling? can you have been tumbling? can they have been tumbling?
Interro-negative form
Simple form
can't I tumble? can't you tumble? can't he tumble? can't we tumble? can't you tumble? can't they tumble?
V-ing form
can't I be tumbling? can't you be tumbling? can't he be tumbling? can't we be tumbling? can't you be tumbling? can't they be tumbling?
Perfect
can't I have tumbled? can't you have tumbled? can't he have tumbled? can't we have tumbled? can't you have tumbled? can't they have tumbled?
V-ing perfect
can't I have been tumbling? can't you have been tumbling? can't he have been tumbling? can't we have been tumbling? can't you have been tumbling? can't they have been tumbling?