English verb conjugation
COULD NIBBLE

Regular verb: nibble - nibbled - nibbled

Affirmation

Simple form	V-ing form
I could nibble you could nibble he could nibble we could nibble you could nibble they could nibble	I could be nibbling you could be nibbling he could be nibbling we could be nibbling you could be nibbling they could be nibbling
Perfect	V-ing perfect
I could have nibbled you could have nibbled he could have nibbled we could have nibbled you could have nibbled they could have nibbled	I could have been nibbling you could have been nibbling he could have been nibbling we could have been nibbling you could have been nibbling they could have been nibbling

Negation

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

Interrogative form

Simple form	V-ing form
could I nibble? could you nibble? could he nibble? could we nibble? could you nibble? could they nibble?	could I be nibbling? could you be nibbling? could he be nibbling? could we be nibbling? could you be nibbling? could they be nibbling?
Perfect	V-ing perfect
could I have nibbled? could you have nibbled? could he have nibbled? could we have nibbled? could you have nibbled? could they have nibbled?	could I have been nibbling? could you have been nibbling? could he have been nibbling? could we have been nibbling? could you have been nibbling? could they have been nibbling?

Interro-negative form

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