I could engineer you could engineer she could engineer we could engineer you could engineer they could engineer
V-ing form
I could be engineering you could be engineering she could be engineering we could be engineering you could be engineering they could be engineering
Perfect
I could have engineered you could have engineered she could have engineered we could have engineered you could have engineered they could have engineered
V-ing perfect
I could have been engineering you could have been engineering she could have been engineering we could have been engineering you could have been engineering they could have been engineering
Negation
Simple form
I could not engineer you could not engineer she could not engineer we could not engineer you could not engineer they could not engineer
V-ing form
I could not be engineering you could not be engineering she could not be engineering we could not be engineering you could not be engineering they could not be engineering
Perfect
I could not have engineered you could not have engineered she could not have engineered we could not have engineered you could not have engineered they could not have engineered
V-ing perfect
I could not have been engineering you could not have been engineering she could not have been engineering we could not have been engineering you could not have been engineering they could not have been engineering
Interrogative form
Simple form
could I engineer? could you engineer? could she engineer? could we engineer? could you engineer? could they engineer?
V-ing form
could I be engineering? could you be engineering? could she be engineering? could we be engineering? could you be engineering? could they be engineering?
Perfect
could I have engineered? could you have engineered? could she have engineered? could we have engineered? could you have engineered? could they have engineered?
V-ing perfect
could I have been engineering? could you have been engineering? could she have been engineering? could we have been engineering? could you have been engineering? could they have been engineering?
Interro-negative form
Simple form
could I not engineer? could you not engineer? could she not engineer? could we not engineer? could you not engineer? could they not engineer?
V-ing form
could I not be engineering? could you not be engineering? could she not be engineering? could we not be engineering? could you not be engineering? could they not be engineering?
Perfect
could I not have engineered? could you not have engineered? could she not have engineered? could we not have engineered? could you not have engineered? could they not have engineered?
V-ing perfect
could I not have been engineering? could you not have been engineering? could she not have been engineering? could we not have been engineering? could you not have been engineering? could they not have been engineering?