English verb conjugation
COULD BOB

Regular verb: bob - bobbed - bobbed

Affirmation

Simple form	V-ing form
I could bob you could bob he could bob we could bob you could bob they could bob	I could be bobbing you could be bobbing he could be bobbing we could be bobbing you could be bobbing they could be bobbing
Perfect	V-ing perfect
I could have bobbed you could have bobbed he could have bobbed we could have bobbed you could have bobbed they could have bobbed	I could have been bobbing you could have been bobbing he could have been bobbing we could have been bobbing you could have been bobbing they could have been bobbing

Negation

Simple form	V-ing form
I couldn't bob you couldn't bob he couldn't bob we couldn't bob you couldn't bob they couldn't bob	I couldn't be bobbing you couldn't be bobbing he couldn't be bobbing we couldn't be bobbing you couldn't be bobbing they couldn't be bobbing
Perfect	V-ing perfect
I couldn't have bobbed you couldn't have bobbed he couldn't have bobbed we couldn't have bobbed you couldn't have bobbed they couldn't have bobbed	I couldn't have been bobbing you couldn't have been bobbing he couldn't have been bobbing we couldn't have been bobbing you couldn't have been bobbing they couldn't have been bobbing

Interrogative form

Simple form	V-ing form
could I bob? could you bob? could he bob? could we bob? could you bob? could they bob?	could I be bobbing? could you be bobbing? could he be bobbing? could we be bobbing? could you be bobbing? could they be bobbing?
Perfect	V-ing perfect
could I have bobbed? could you have bobbed? could he have bobbed? could we have bobbed? could you have bobbed? could they have bobbed?	could I have been bobbing? could you have been bobbing? could he have been bobbing? could we have been bobbing? could you have been bobbing? could they have been bobbing?

Interro-negative form

Simple form	V-ing form
couldn't I bob? couldn't you bob? couldn't he bob? couldn't we bob? couldn't you bob? couldn't they bob?	couldn't I be bobbing? couldn't you be bobbing? couldn't he be bobbing? couldn't we be bobbing? couldn't you be bobbing? couldn't they be bobbing?
Perfect	V-ing perfect
couldn't I have bobbed? couldn't you have bobbed? couldn't he have bobbed? couldn't we have bobbed? couldn't you have bobbed? couldn't they have bobbed?	couldn't I have been bobbing? couldn't you have been bobbing? couldn't he have been bobbing? couldn't we have been bobbing? couldn't you have been bobbing? couldn't they have been bobbing?