English verb conjugation
COULD TILLER

Regular verb: tiller - tillered - tillered

Affirmation

Simple form	V-ing form
I could tiller you could tiller he could tiller we could tiller you could tiller they could tiller	I could be tillering you could be tillering he could be tillering we could be tillering you could be tillering they could be tillering
Perfect	V-ing perfect
I could have tillered you could have tillered he could have tillered we could have tillered you could have tillered they could have tillered	I could have been tillering you could have been tillering he could have been tillering we could have been tillering you could have been tillering they could have been tillering

Negation

Simple form	V-ing form
I couldn't tiller you couldn't tiller he couldn't tiller we couldn't tiller you couldn't tiller they couldn't tiller	I couldn't be tillering you couldn't be tillering he couldn't be tillering we couldn't be tillering you couldn't be tillering they couldn't be tillering
Perfect	V-ing perfect
I couldn't have tillered you couldn't have tillered he couldn't have tillered we couldn't have tillered you couldn't have tillered they couldn't have tillered	I couldn't have been tillering you couldn't have been tillering he couldn't have been tillering we couldn't have been tillering you couldn't have been tillering they couldn't have been tillering

Interrogative form

Simple form	V-ing form
could I tiller? could you tiller? could he tiller? could we tiller? could you tiller? could they tiller?	could I be tillering? could you be tillering? could he be tillering? could we be tillering? could you be tillering? could they be tillering?
Perfect	V-ing perfect
could I have tillered? could you have tillered? could he have tillered? could we have tillered? could you have tillered? could they have tillered?	could I have been tillering? could you have been tillering? could he have been tillering? could we have been tillering? could you have been tillering? could they have been tillering?

Interro-negative form

Simple form	V-ing form
couldn't I tiller? couldn't you tiller? couldn't he tiller? couldn't we tiller? couldn't you tiller? couldn't they tiller?	couldn't I be tillering? couldn't you be tillering? couldn't he be tillering? couldn't we be tillering? couldn't you be tillering? couldn't they be tillering?
Perfect	V-ing perfect
couldn't I have tillered? couldn't you have tillered? couldn't he have tillered? couldn't we have tillered? couldn't you have tillered? couldn't they have tillered?	couldn't I have been tillering? couldn't you have been tillering? couldn't he have been tillering? couldn't we have been tillering? couldn't you have been tillering? couldn't they have been tillering?