I can nibble you can nibble he can nibble we can nibble you can nibble they can nibble
V-ing form
I can be nibbling you can be nibbling he can be nibbling we can be nibbling you can be nibbling they can be nibbling
Perfect
I can have nibbled you can have nibbled he can have nibbled we can have nibbled you can have nibbled they can have nibbled
V-ing perfect
I can have been nibbling you can have been nibbling he can have been nibbling we can have been nibbling you can have been nibbling they can have been nibbling
Negation
Simple form
I can't nibble you can't nibble he can't nibble we can't nibble you can't nibble they can't nibble
V-ing form
I can't be nibbling you can't be nibbling he can't be nibbling we can't be nibbling you can't be nibbling they can't be nibbling
Perfect
I can't have nibbled you can't have nibbled he can't have nibbled we can't have nibbled you can't have nibbled they can't have nibbled
V-ing perfect
I can't have been nibbling you can't have been nibbling he can't have been nibbling we can't have been nibbling you can't have been nibbling they can't have been nibbling
Interrogative form
Simple form
can I nibble? can you nibble? can he nibble? can we nibble? can you nibble? can they nibble?
V-ing form
can I be nibbling? can you be nibbling? can he be nibbling? can we be nibbling? can you be nibbling? can they be nibbling?
Perfect
can I have nibbled? can you have nibbled? can he have nibbled? can we have nibbled? can you have nibbled? can they have nibbled?
V-ing perfect
can I have been nibbling? can you have been nibbling? can he have been nibbling? can we have been nibbling? can you have been nibbling? can they have been nibbling?
Interro-negative form
Simple form
can't I nibble? can't you nibble? can't he nibble? can't we nibble? can't you nibble? can't they nibble?
V-ing form
can't I be nibbling? can't you be nibbling? can't he be nibbling? can't we be nibbling? can't you be nibbling? can't they be nibbling?
Perfect
can't I have nibbled? can't you have nibbled? can't he have nibbled? can't we have nibbled? can't you have nibbled? can't they have nibbled?
V-ing perfect
can't I have been nibbling? can't you have been nibbling? can't he have been nibbling? can't we have been nibbling? can't you have been nibbling? can't they have been nibbling?