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 couldn't titter you couldn't titter he couldn't titter we couldn't titter you couldn't titter they couldn't titter	I couldn't be tittering you couldn't be tittering he couldn't be tittering we couldn't be tittering you couldn't be tittering they couldn't be tittering
Perfect	V-ing perfect
I couldn't have tittered you couldn't have tittered he couldn't have tittered we couldn't have tittered you couldn't have tittered they couldn't have tittered	I couldn't have been tittering you couldn't have been tittering he couldn't have been tittering we couldn't have been tittering you couldn't have been tittering they couldn't 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
couldn't I titter? couldn't you titter? couldn't he titter? couldn't we titter? couldn't you titter? couldn't they titter?	couldn't I be tittering? couldn't you be tittering? couldn't he be tittering? couldn't we be tittering? couldn't you be tittering? couldn't they be tittering?
Perfect	V-ing perfect
couldn't I have tittered? couldn't you have tittered? couldn't he have tittered? couldn't we have tittered? couldn't you have tittered? couldn't they have tittered?	couldn't I have been tittering? couldn't you have been tittering? couldn't he have been tittering? couldn't we have been tittering? couldn't you have been tittering? couldn't they have been tittering?