I can fumble you can fumble he can fumble we can fumble you can fumble they can fumble
V-ing form
I can be fumbling you can be fumbling he can be fumbling we can be fumbling you can be fumbling they can be fumbling
Perfect
I can have fumbled you can have fumbled he can have fumbled we can have fumbled you can have fumbled they can have fumbled
V-ing perfect
I can have been fumbling you can have been fumbling he can have been fumbling we can have been fumbling you can have been fumbling they can have been fumbling
Negation
Simple form
I can't fumble you can't fumble he can't fumble we can't fumble you can't fumble they can't fumble
V-ing form
I can't be fumbling you can't be fumbling he can't be fumbling we can't be fumbling you can't be fumbling they can't be fumbling
Perfect
I can't have fumbled you can't have fumbled he can't have fumbled we can't have fumbled you can't have fumbled they can't have fumbled
V-ing perfect
I can't have been fumbling you can't have been fumbling he can't have been fumbling we can't have been fumbling you can't have been fumbling they can't have been fumbling
Interrogative form
Simple form
can I fumble? can you fumble? can he fumble? can we fumble? can you fumble? can they fumble?
V-ing form
can I be fumbling? can you be fumbling? can he be fumbling? can we be fumbling? can you be fumbling? can they be fumbling?
Perfect
can I have fumbled? can you have fumbled? can he have fumbled? can we have fumbled? can you have fumbled? can they have fumbled?
V-ing perfect
can I have been fumbling? can you have been fumbling? can he have been fumbling? can we have been fumbling? can you have been fumbling? can they have been fumbling?
Interro-negative form
Simple form
can't I fumble? can't you fumble? can't he fumble? can't we fumble? can't you fumble? can't they fumble?
V-ing form
can't I be fumbling? can't you be fumbling? can't he be fumbling? can't we be fumbling? can't you be fumbling? can't they be fumbling?
Perfect
can't I have fumbled? can't you have fumbled? can't he have fumbled? can't we have fumbled? can't you have fumbled? can't they have fumbled?
V-ing perfect
can't I have been fumbling? can't you have been fumbling? can't he have been fumbling? can't we have been fumbling? can't you have been fumbling? can't they have been fumbling?