English verb conjugation
COULD GRAPH

Regular verb: graph - graphed - graphed

Affirmation

Simple form	V-ing form
I could graph you could graph she could graph we could graph you could graph they could graph	I could be graphing you could be graphing she could be graphing we could be graphing you could be graphing they could be graphing
Perfect	V-ing perfect
I could have graphed you could have graphed she could have graphed we could have graphed you could have graphed they could have graphed	I could have been graphing you could have been graphing she could have been graphing we could have been graphing you could have been graphing they could have been graphing

Negation

Simple form	V-ing form
I could not graph you could not graph she could not graph we could not graph you could not graph they could not graph	I could not be graphing you could not be graphing she could not be graphing we could not be graphing you could not be graphing they could not be graphing
Perfect	V-ing perfect
I could not have graphed you could not have graphed she could not have graphed we could not have graphed you could not have graphed they could not have graphed	I could not have been graphing you could not have been graphing she could not have been graphing we could not have been graphing you could not have been graphing they could not have been graphing

Interrogative form

Simple form	V-ing form
could I graph? could you graph? could she graph? could we graph? could you graph? could they graph?	could I be graphing? could you be graphing? could she be graphing? could we be graphing? could you be graphing? could they be graphing?
Perfect	V-ing perfect
could I have graphed? could you have graphed? could she have graphed? could we have graphed? could you have graphed? could they have graphed?	could I have been graphing? could you have been graphing? could she have been graphing? could we have been graphing? could you have been graphing? could they have been graphing?

Interro-negative form

Simple form	V-ing form
could I not graph? could you not graph? could she not graph? could we not graph? could you not graph? could they not graph?	could I not be graphing? could you not be graphing? could she not be graphing? could we not be graphing? could you not be graphing? could they not be graphing?
Perfect	V-ing perfect
could I not have graphed? could you not have graphed? could she not have graphed? could we not have graphed? could you not have graphed? could they not have graphed?	could I not have been graphing? could you not have been graphing? could she not have been graphing? could we not have been graphing? could you not have been graphing? could they not have been graphing?