English verb conjugation
COULD BUBBLE

Regular verb: bubble - bubbled - bubbled

Affirmation

Simple form	V-ing form
I could bubble you could bubble he could bubble we could bubble you could bubble they could bubble	I could be bubbling you could be bubbling he could be bubbling we could be bubbling you could be bubbling they could be bubbling
Perfect	V-ing perfect
I could have bubbled you could have bubbled he could have bubbled we could have bubbled you could have bubbled they could have bubbled	I could have been bubbling you could have been bubbling he could have been bubbling we could have been bubbling you could have been bubbling they could have been bubbling

Negation

Simple form	V-ing form
I couldn't bubble you couldn't bubble he couldn't bubble we couldn't bubble you couldn't bubble they couldn't bubble	I couldn't be bubbling you couldn't be bubbling he couldn't be bubbling we couldn't be bubbling you couldn't be bubbling they couldn't be bubbling
Perfect	V-ing perfect
I couldn't have bubbled you couldn't have bubbled he couldn't have bubbled we couldn't have bubbled you couldn't have bubbled they couldn't have bubbled	I couldn't have been bubbling you couldn't have been bubbling he couldn't have been bubbling we couldn't have been bubbling you couldn't have been bubbling they couldn't have been bubbling

Interrogative form

Simple form	V-ing form
could I bubble? could you bubble? could he bubble? could we bubble? could you bubble? could they bubble?	could I be bubbling? could you be bubbling? could he be bubbling? could we be bubbling? could you be bubbling? could they be bubbling?
Perfect	V-ing perfect
could I have bubbled? could you have bubbled? could he have bubbled? could we have bubbled? could you have bubbled? could they have bubbled?	could I have been bubbling? could you have been bubbling? could he have been bubbling? could we have been bubbling? could you have been bubbling? could they have been bubbling?

Interro-negative form

Simple form	V-ing form
couldn't I bubble? couldn't you bubble? couldn't he bubble? couldn't we bubble? couldn't you bubble? couldn't they bubble?	couldn't I be bubbling? couldn't you be bubbling? couldn't he be bubbling? couldn't we be bubbling? couldn't you be bubbling? couldn't they be bubbling?
Perfect	V-ing perfect
couldn't I have bubbled? couldn't you have bubbled? couldn't he have bubbled? couldn't we have bubbled? couldn't you have bubbled? couldn't they have bubbled?	couldn't I have been bubbling? couldn't you have been bubbling? couldn't he have been bubbling? couldn't we have been bubbling? couldn't you have been bubbling? couldn't they have been bubbling?