English verb conjugation
COULD WARBLE

Regular verb: warble - warbled - warbled

Affirmation

Simple form	V-ing form
I could warble you could warble she could warble we could warble you could warble they could warble	I could be warbling you could be warbling she 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 she 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 she 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 couldn't warble you couldn't warble she couldn't warble we couldn't warble you couldn't warble they couldn't warble	I couldn't be warbling you couldn't be warbling she couldn't be warbling we couldn't be warbling you couldn't be warbling they couldn't be warbling
Perfect	V-ing perfect
I couldn't have warbled you couldn't have warbled she couldn't have warbled we couldn't have warbled you couldn't have warbled they couldn't have warbled	I couldn't have been warbling you couldn't have been warbling she couldn't have been warbling we couldn't have been warbling you couldn't have been warbling they couldn't have been warbling

Interrogative form

Simple form	V-ing form
could I warble? could you warble? could she warble? could we warble? could you warble? could they warble?	could I be warbling? could you be warbling? could she 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 she 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 she 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
couldn't I warble? couldn't you warble? couldn't she warble? couldn't we warble? couldn't you warble? couldn't they warble?	couldn't I be warbling? couldn't you be warbling? couldn't she be warbling? couldn't we be warbling? couldn't you be warbling? couldn't they be warbling?
Perfect	V-ing perfect
couldn't I have warbled? couldn't you have warbled? couldn't she have warbled? couldn't we have warbled? couldn't you have warbled? couldn't they have warbled?	couldn't I have been warbling? couldn't you have been warbling? couldn't she have been warbling? couldn't we have been warbling? couldn't you have been warbling? couldn't they have been warbling?