could tub
Regular verb: tub - tubbed- tubbed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
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	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 	Perfect 	V-ing perfect 	
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	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 	Perfect 	V-ing perfect 	
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? 	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 	Perfect 	V-ing perfect 	
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? 	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?