English verb conjugation
COULD TITTER

Regular verb: titter - tittered - tittered

Affirmation

Simple form	V-ing form
I could titter you could titter he could titter we could titter you could titter they could titter	I could be tittering you could be tittering he could be tittering we could be tittering you could be tittering they could be tittering
Perfect	V-ing perfect
I could have tittered you could have tittered he could have tittered we could have tittered you could have tittered they could have tittered	I could have been tittering you could have been tittering he could have been tittering we could have been tittering you could have been tittering they could have been tittering

Negation

Simple form	V-ing form
I could not titter you could not titter he could not titter we could not titter you could not titter they could not titter	I could not be tittering you could not be tittering he could not be tittering we could not be tittering you could not be tittering they could not be tittering
Perfect	V-ing perfect
I could not have tittered you could not have tittered he could not have tittered we could not have tittered you could not have tittered they could not have tittered	I could not have been tittering you could not have been tittering he could not have been tittering we could not have been tittering you could not have been tittering they could not have been tittering

Interrogative form

Simple form	V-ing form
could I titter? could you titter? could he titter? could we titter? could you titter? could they titter?	could I be tittering? could you be tittering? could he be tittering? could we be tittering? could you be tittering? could they be tittering?
Perfect	V-ing perfect
could I have tittered? could you have tittered? could he have tittered? could we have tittered? could you have tittered? could they have tittered?	could I have been tittering? could you have been tittering? could he have been tittering? could we have been tittering? could you have been tittering? could they have been tittering?

Interro-negative form

Simple form	V-ing form
could I not titter? could you not titter? could he not titter? could we not titter? could you not titter? could they not titter?	could I not be tittering? could you not be tittering? could he not be tittering? could we not be tittering? could you not be tittering? could they not be tittering?
Perfect	V-ing perfect
could I not have tittered? could you not have tittered? could he not have tittered? could we not have tittered? could you not have tittered? could they not have tittered?	could I not have been tittering? could you not have been tittering? could he not have been tittering? could we not have been tittering? could you not have been tittering? could they not have been tittering?