I can nibble you can nibble she can nibble we can nibble you can nibble they can nibble
V-ing form
I can be nibbling you can be nibbling she can be nibbling we can be nibbling you can be nibbling they can be nibbling
Perfect
I can have nibbled you can have nibbled she 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 she can have been nibbling we can have been nibbling you can have been nibbling they can have been nibbling
Negation
Simple form
I cannot nibble you cannot nibble she cannot nibble we cannot nibble you cannot nibble they cannot nibble
V-ing form
I cannot be nibbling you cannot be nibbling she cannot be nibbling we cannot be nibbling you cannot be nibbling they cannot be nibbling
Perfect
I cannot have nibbled you cannot have nibbled she cannot have nibbled we cannot have nibbled you cannot have nibbled they cannot have nibbled
V-ing perfect
I cannot have been nibbling you cannot have been nibbling she cannot have been nibbling we cannot have been nibbling you cannot have been nibbling they cannot have been nibbling
Interrogative form
Simple form
can I nibble? can you nibble? can she nibble? can we nibble? can you nibble? can they nibble?
V-ing form
can I be nibbling? can you be nibbling? can she be nibbling? can we be nibbling? can you be nibbling? can they be nibbling?
Perfect
can I have nibbled? can you have nibbled? can she 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 she have been nibbling? can we have been nibbling? can you have been nibbling? can they have been nibbling?
Interro-negative form
Simple form
can I not nibble? can you not nibble? can she not nibble? can we not nibble? can you not nibble? can they not nibble?
V-ing form
can I not be nibbling? can you not be nibbling? can she not be nibbling? can we not be nibbling? can you not be nibbling? can they not be nibbling?
Perfect
can I not have nibbled? can you not have nibbled? can she not have nibbled? can we not have nibbled? can you not have nibbled? can they not have nibbled?
V-ing perfect
can I not have been nibbling? can you not have been nibbling? can she not have been nibbling? can we not have been nibbling? can you not have been nibbling? can they not have been nibbling?