English verb conjugation
COULD OVERBILL

Regular verb: overbill - overbilled - overbilled

Affirmation

Simple form	V-ing form
I could overbill you could overbill he could overbill we could overbill you could overbill they could overbill	I could be overbilling you could be overbilling he could be overbilling we could be overbilling you could be overbilling they could be overbilling
Perfect	V-ing perfect
I could have overbilled you could have overbilled he could have overbilled we could have overbilled you could have overbilled they could have overbilled	I could have been overbilling you could have been overbilling he could have been overbilling we could have been overbilling you could have been overbilling they could have been overbilling

Negation

Simple form	V-ing form
I couldn't overbill you couldn't overbill he couldn't overbill we couldn't overbill you couldn't overbill they couldn't overbill	I couldn't be overbilling you couldn't be overbilling he couldn't be overbilling we couldn't be overbilling you couldn't be overbilling they couldn't be overbilling
Perfect	V-ing perfect
I couldn't have overbilled you couldn't have overbilled he couldn't have overbilled we couldn't have overbilled you couldn't have overbilled they couldn't have overbilled	I couldn't have been overbilling you couldn't have been overbilling he couldn't have been overbilling we couldn't have been overbilling you couldn't have been overbilling they couldn't have been overbilling

Interrogative form

Simple form	V-ing form
could I overbill? could you overbill? could he overbill? could we overbill? could you overbill? could they overbill?	could I be overbilling? could you be overbilling? could he be overbilling? could we be overbilling? could you be overbilling? could they be overbilling?
Perfect	V-ing perfect
could I have overbilled? could you have overbilled? could he have overbilled? could we have overbilled? could you have overbilled? could they have overbilled?	could I have been overbilling? could you have been overbilling? could he have been overbilling? could we have been overbilling? could you have been overbilling? could they have been overbilling?

Interro-negative form

Simple form	V-ing form
couldn't I overbill? couldn't you overbill? couldn't he overbill? couldn't we overbill? couldn't you overbill? couldn't they overbill?	couldn't I be overbilling? couldn't you be overbilling? couldn't he be overbilling? couldn't we be overbilling? couldn't you be overbilling? couldn't they be overbilling?
Perfect	V-ing perfect
couldn't I have overbilled? couldn't you have overbilled? couldn't he have overbilled? couldn't we have overbilled? couldn't you have overbilled? couldn't they have overbilled?	couldn't I have been overbilling? couldn't you have been overbilling? couldn't he have been overbilling? couldn't we have been overbilling? couldn't you have been overbilling? couldn't they have been overbilling?