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 couldn't tub you couldn't tub he couldn't tub we couldn't tub you couldn't tub they couldn't tub	I couldn't be tubbing you couldn't be tubbing he couldn't be tubbing we couldn't be tubbing you couldn't be tubbing they couldn't be tubbing
Perfect	V-ing perfect
I couldn't have tubbed you couldn't have tubbed he couldn't have tubbed we couldn't have tubbed you couldn't have tubbed they couldn't have tubbed	I couldn't have been tubbing you couldn't have been tubbing he couldn't have been tubbing we couldn't have been tubbing you couldn't have been tubbing they couldn't 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
couldn't I tub? couldn't you tub? couldn't he tub? couldn't we tub? couldn't you tub? couldn't they tub?	couldn't I be tubbing? couldn't you be tubbing? couldn't he be tubbing? couldn't we be tubbing? couldn't you be tubbing? couldn't they be tubbing?
Perfect	V-ing perfect
couldn't I have tubbed? couldn't you have tubbed? couldn't he have tubbed? couldn't we have tubbed? couldn't you have tubbed? couldn't they have tubbed?	couldn't I have been tubbing? couldn't you have been tubbing? couldn't he have been tubbing? couldn't we have been tubbing? couldn't you have been tubbing? couldn't they have been tubbing?