I could gradate you could gradate he could gradate we could gradate you could gradate they could gradate
V-ing form
I could be gradating you could be gradating he could be gradating we could be gradating you could be gradating they could be gradating
Perfect
I could have gradated you could have gradated he could have gradated we could have gradated you could have gradated they could have gradated
V-ing perfect
I could have been gradating you could have been gradating he could have been gradating we could have been gradating you could have been gradating they could have been gradating
Negation
Simple form
I could not gradate you could not gradate he could not gradate we could not gradate you could not gradate they could not gradate
V-ing form
I could not be gradating you could not be gradating he could not be gradating we could not be gradating you could not be gradating they could not be gradating
Perfect
I could not have gradated you could not have gradated he could not have gradated we could not have gradated you could not have gradated they could not have gradated
V-ing perfect
I could not have been gradating you could not have been gradating he could not have been gradating we could not have been gradating you could not have been gradating they could not have been gradating
Interrogative form
Simple form
could I gradate? could you gradate? could he gradate? could we gradate? could you gradate? could they gradate?
V-ing form
could I be gradating? could you be gradating? could he be gradating? could we be gradating? could you be gradating? could they be gradating?
Perfect
could I have gradated? could you have gradated? could he have gradated? could we have gradated? could you have gradated? could they have gradated?
V-ing perfect
could I have been gradating? could you have been gradating? could he have been gradating? could we have been gradating? could you have been gradating? could they have been gradating?
Interro-negative form
Simple form
could I not gradate? could you not gradate? could he not gradate? could we not gradate? could you not gradate? could they not gradate?
V-ing form
could I not be gradating? could you not be gradating? could he not be gradating? could we not be gradating? could you not be gradating? could they not be gradating?
Perfect
could I not have gradated? could you not have gradated? could he not have gradated? could we not have gradated? could you not have gradated? could they not have gradated?
V-ing perfect
could I not have been gradating? could you not have been gradating? could he not have been gradating? could we not have been gradating? could you not have been gradating? could they not have been gradating?