can nibble
Regular verb: nibble - nibbled- nibbled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can nibble
you can nibble
he can nibble
we can nibble
you can nibble
they can nibble 	I can be nibbling
you can be nibbling
he can be nibbling
we can be nibbling
you can be nibbling
they can be nibbling	I can have nibbled
you can have nibbled
he can have nibbled
we can have nibbled
you can have nibbled
they can have nibbled	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 	V-ing form 	Perfect 	V-ing perfect 	
I cannot nibble
you cannot nibble
he cannot nibble
we cannot nibble
you cannot nibble
they cannot nibble 	I cannot be nibbling
you cannot be nibbling
he cannot be nibbling
we cannot be nibbling
you cannot be nibbling
they cannot be nibbling	I cannot have nibbled
you cannot have nibbled
he cannot have nibbled
we cannot have nibbled
you cannot have nibbled
they cannot have nibbled	I cannot have been nibbling
you cannot have been nibbling
he cannot have been nibbling
we cannot have been nibbling
you cannot have been nibbling
they cannot have been nibbling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I nibble?
can you nibble?
can he nibble?
can we nibble?
can you nibble?
can they nibble? 	can I be nibbling?
can you be nibbling?
can he be nibbling?
can we be nibbling?
can you be nibbling?
can they be nibbling? 	can I have nibbled?
can you have nibbled?
can he have nibbled?
can we have nibbled?
can you have nibbled?
can they have nibbled? 	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 	V-ing form 	Perfect 	V-ing perfect 	
can I not nibble?
can you not nibble?
can he not nibble?
can we not nibble?
can you not nibble?
can they not nibble? 	can I not be nibbling?
can you not be nibbling?
can he not be nibbling?
can we not be nibbling?
can you not be nibbling?
can they not be nibbling? 	can I not have nibbled?
can you not have nibbled?
can he not have nibbled?
can we not have nibbled?
can you not have nibbled?
can they not have nibbled? 	can I not have been nibbling?
can you not have been nibbling?
can he not have been nibbling?
can we not have been nibbling?
can you not have been nibbling?
can they not have been nibbling?