I can bumble you can bumble he can bumble we can bumble you can bumble they can bumble
V-ing form
I can be bumbling you can be bumbling he can be bumbling we can be bumbling you can be bumbling they can be bumbling
Perfect
I can have bumbled you can have bumbled he can have bumbled we can have bumbled you can have bumbled they can have bumbled
V-ing perfect
I can have been bumbling you can have been bumbling he can have been bumbling we can have been bumbling you can have been bumbling they can have been bumbling
Negation
Simple form
I cannot bumble you cannot bumble he cannot bumble we cannot bumble you cannot bumble they cannot bumble
V-ing form
I cannot be bumbling you cannot be bumbling he cannot be bumbling we cannot be bumbling you cannot be bumbling they cannot be bumbling
Perfect
I cannot have bumbled you cannot have bumbled he cannot have bumbled we cannot have bumbled you cannot have bumbled they cannot have bumbled
V-ing perfect
I cannot have been bumbling you cannot have been bumbling he cannot have been bumbling we cannot have been bumbling you cannot have been bumbling they cannot have been bumbling
Interrogative form
Simple form
can I bumble? can you bumble? can he bumble? can we bumble? can you bumble? can they bumble?
V-ing form
can I be bumbling? can you be bumbling? can he be bumbling? can we be bumbling? can you be bumbling? can they be bumbling?
Perfect
can I have bumbled? can you have bumbled? can he have bumbled? can we have bumbled? can you have bumbled? can they have bumbled?
V-ing perfect
can I have been bumbling? can you have been bumbling? can he have been bumbling? can we have been bumbling? can you have been bumbling? can they have been bumbling?
Interro-negative form
Simple form
can I not bumble? can you not bumble? can he not bumble? can we not bumble? can you not bumble? can they not bumble?
V-ing form
can I not be bumbling? can you not be bumbling? can he not be bumbling? can we not be bumbling? can you not be bumbling? can they not be bumbling?
Perfect
can I not have bumbled? can you not have bumbled? can he not have bumbled? can we not have bumbled? can you not have bumbled? can they not have bumbled?
V-ing perfect
can I not have been bumbling? can you not have been bumbling? can he not have been bumbling? can we not have been bumbling? can you not have been bumbling? can they not have been bumbling?