English verb conjugation
COULD WARBLE

Regular verb: warble - warbled - warbled

Affirmation

Simple form	V-ing form
I could warble you could warble he could warble we could warble you could warble they could warble	I could be warbling you could be warbling he could be warbling we could be warbling you could be warbling they could be warbling
Perfect	V-ing perfect
I could have warbled you could have warbled he could have warbled we could have warbled you could have warbled they could have warbled	I could have been warbling you could have been warbling he could have been warbling we could have been warbling you could have been warbling they could have been warbling

Negation

Simple form	V-ing form
I could not warble you could not warble he could not warble we could not warble you could not warble they could not warble	I could not be warbling you could not be warbling he could not be warbling we could not be warbling you could not be warbling they could not be warbling
Perfect	V-ing perfect
I could not have warbled you could not have warbled he could not have warbled we could not have warbled you could not have warbled they could not have warbled	I could not have been warbling you could not have been warbling he could not have been warbling we could not have been warbling you could not have been warbling they could not have been warbling

Interrogative form

Simple form	V-ing form
could I warble? could you warble? could he warble? could we warble? could you warble? could they warble?	could I be warbling? could you be warbling? could he be warbling? could we be warbling? could you be warbling? could they be warbling?
Perfect	V-ing perfect
could I have warbled? could you have warbled? could he have warbled? could we have warbled? could you have warbled? could they have warbled?	could I have been warbling? could you have been warbling? could he have been warbling? could we have been warbling? could you have been warbling? could they have been warbling?

Interro-negative form

Simple form	V-ing form
could I not warble? could you not warble? could he not warble? could we not warble? could you not warble? could they not warble?	could I not be warbling? could you not be warbling? could he not be warbling? could we not be warbling? could you not be warbling? could they not be warbling?
Perfect	V-ing perfect
could I not have warbled? could you not have warbled? could he not have warbled? could we not have warbled? could you not have warbled? could they not have warbled?	could I not have been warbling? could you not have been warbling? could he not have been warbling? could we not have been warbling? could you not have been warbling? could they not have been warbling?