English verb conjugation
COULD INVOICE

Regular verb: invoice - invoiced - invoiced

Affirmation

Simple form	V-ing form
I could invoice you could invoice he could invoice we could invoice you could invoice they could invoice	I could be invoicing you could be invoicing he could be invoicing we could be invoicing you could be invoicing they could be invoicing
Perfect	V-ing perfect
I could have invoiced you could have invoiced he could have invoiced we could have invoiced you could have invoiced they could have invoiced	I could have been invoicing you could have been invoicing he could have been invoicing we could have been invoicing you could have been invoicing they could have been invoicing

Negation

Simple form	V-ing form
I couldn't invoice you couldn't invoice he couldn't invoice we couldn't invoice you couldn't invoice they couldn't invoice	I couldn't be invoicing you couldn't be invoicing he couldn't be invoicing we couldn't be invoicing you couldn't be invoicing they couldn't be invoicing
Perfect	V-ing perfect
I couldn't have invoiced you couldn't have invoiced he couldn't have invoiced we couldn't have invoiced you couldn't have invoiced they couldn't have invoiced	I couldn't have been invoicing you couldn't have been invoicing he couldn't have been invoicing we couldn't have been invoicing you couldn't have been invoicing they couldn't have been invoicing

Interrogative form

Simple form	V-ing form
could I invoice? could you invoice? could he invoice? could we invoice? could you invoice? could they invoice?	could I be invoicing? could you be invoicing? could he be invoicing? could we be invoicing? could you be invoicing? could they be invoicing?
Perfect	V-ing perfect
could I have invoiced? could you have invoiced? could he have invoiced? could we have invoiced? could you have invoiced? could they have invoiced?	could I have been invoicing? could you have been invoicing? could he have been invoicing? could we have been invoicing? could you have been invoicing? could they have been invoicing?

Interro-negative form

Simple form	V-ing form
couldn't I invoice? couldn't you invoice? couldn't he invoice? couldn't we invoice? couldn't you invoice? couldn't they invoice?	couldn't I be invoicing? couldn't you be invoicing? couldn't he be invoicing? couldn't we be invoicing? couldn't you be invoicing? couldn't they be invoicing?
Perfect	V-ing perfect
couldn't I have invoiced? couldn't you have invoiced? couldn't he have invoiced? couldn't we have invoiced? couldn't you have invoiced? couldn't they have invoiced?	couldn't I have been invoicing? couldn't you have been invoicing? couldn't he have been invoicing? couldn't we have been invoicing? couldn't you have been invoicing? couldn't they have been invoicing?