English verb conjugation
COULD STUB

Regular verb: stub - stubbed - stubbed

Affirmation

Simple form	V-ing form
I could stub you could stub he could stub we could stub you could stub they could stub	I could be stubbing you could be stubbing he could be stubbing we could be stubbing you could be stubbing they could be stubbing
Perfect	V-ing perfect
I could have stubbed you could have stubbed he could have stubbed we could have stubbed you could have stubbed they could have stubbed	I could have been stubbing you could have been stubbing he could have been stubbing we could have been stubbing you could have been stubbing they could have been stubbing

Negation

Simple form	V-ing form
I could not stub you could not stub he could not stub we could not stub you could not stub they could not stub	I could not be stubbing you could not be stubbing he could not be stubbing we could not be stubbing you could not be stubbing they could not be stubbing
Perfect	V-ing perfect
I could not have stubbed you could not have stubbed he could not have stubbed we could not have stubbed you could not have stubbed they could not have stubbed	I could not have been stubbing you could not have been stubbing he could not have been stubbing we could not have been stubbing you could not have been stubbing they could not have been stubbing

Interrogative form

Simple form	V-ing form
could I stub? could you stub? could he stub? could we stub? could you stub? could they stub?	could I be stubbing? could you be stubbing? could he be stubbing? could we be stubbing? could you be stubbing? could they be stubbing?
Perfect	V-ing perfect
could I have stubbed? could you have stubbed? could he have stubbed? could we have stubbed? could you have stubbed? could they have stubbed?	could I have been stubbing? could you have been stubbing? could he have been stubbing? could we have been stubbing? could you have been stubbing? could they have been stubbing?

Interro-negative form

Simple form	V-ing form
could I not stub? could you not stub? could he not stub? could we not stub? could you not stub? could they not stub?	could I not be stubbing? could you not be stubbing? could he not be stubbing? could we not be stubbing? could you not be stubbing? could they not be stubbing?
Perfect	V-ing perfect
could I not have stubbed? could you not have stubbed? could he not have stubbed? could we not have stubbed? could you not have stubbed? could they not have stubbed?	could I not have been stubbing? could you not have been stubbing? could he not have been stubbing? could we not have been stubbing? could you not have been stubbing? could they not have been stubbing?