English verb conjugation
COULD TUB

Regular verb: tub - tubbed - tubbed

Affirmation

Simple form	V-ing form
I could tub you could tub he could tub we could tub you could tub they could tub	I could be tubbing you could be tubbing he could be tubbing we could be tubbing you could be tubbing they could be tubbing
Perfect	V-ing perfect
I could have tubbed you could have tubbed he could have tubbed we could have tubbed you could have tubbed they could have tubbed	I could have been tubbing you could have been tubbing he could have been tubbing we could have been tubbing you could have been tubbing they could have been tubbing

Negation

Simple form	V-ing form
I could not tub you could not tub he could not tub we could not tub you could not tub they could not tub	I could not be tubbing you could not be tubbing he could not be tubbing we could not be tubbing you could not be tubbing they could not be tubbing
Perfect	V-ing perfect
I could not have tubbed you could not have tubbed he could not have tubbed we could not have tubbed you could not have tubbed they could not have tubbed	I could not have been tubbing you could not have been tubbing he could not have been tubbing we could not have been tubbing you could not have been tubbing they could not have been tubbing

Interrogative form

Simple form	V-ing form
could I tub? could you tub? could he tub? could we tub? could you tub? could they tub?	could I be tubbing? could you be tubbing? could he be tubbing? could we be tubbing? could you be tubbing? could they be tubbing?
Perfect	V-ing perfect
could I have tubbed? could you have tubbed? could he have tubbed? could we have tubbed? could you have tubbed? could they have tubbed?	could I have been tubbing? could you have been tubbing? could he have been tubbing? could we have been tubbing? could you have been tubbing? could they have been tubbing?

Interro-negative form

Simple form	V-ing form
could I not tub? could you not tub? could he not tub? could we not tub? could you not tub? could they not tub?	could I not be tubbing? could you not be tubbing? could he not be tubbing? could we not be tubbing? could you not be tubbing? could they not be tubbing?
Perfect	V-ing perfect
could I not have tubbed? could you not have tubbed? could he not have tubbed? could we not have tubbed? could you not have tubbed? could they not have tubbed?	could I not have been tubbing? could you not have been tubbing? could he not have been tubbing? could we not have been tubbing? could you not have been tubbing? could they not have been tubbing?