I could grit you could grit he could grit we could grit you could grit they could grit
V-ing form
I could be gritting you could be gritting he could be gritting we could be gritting you could be gritting they could be gritting
Perfect
I could have gritted you could have gritted he could have gritted we could have gritted you could have gritted they could have gritted
V-ing perfect
I could have been gritting you could have been gritting he could have been gritting we could have been gritting you could have been gritting they could have been gritting
Negation
Simple form
I could not grit you could not grit he could not grit we could not grit you could not grit they could not grit
V-ing form
I could not be gritting you could not be gritting he could not be gritting we could not be gritting you could not be gritting they could not be gritting
Perfect
I could not have gritted you could not have gritted he could not have gritted we could not have gritted you could not have gritted they could not have gritted
V-ing perfect
I could not have been gritting you could not have been gritting he could not have been gritting we could not have been gritting you could not have been gritting they could not have been gritting
Interrogative form
Simple form
could I grit? could you grit? could he grit? could we grit? could you grit? could they grit?
V-ing form
could I be gritting? could you be gritting? could he be gritting? could we be gritting? could you be gritting? could they be gritting?
Perfect
could I have gritted? could you have gritted? could he have gritted? could we have gritted? could you have gritted? could they have gritted?
V-ing perfect
could I have been gritting? could you have been gritting? could he have been gritting? could we have been gritting? could you have been gritting? could they have been gritting?
Interro-negative form
Simple form
could I not grit? could you not grit? could he not grit? could we not grit? could you not grit? could they not grit?
V-ing form
could I not be gritting? could you not be gritting? could he not be gritting? could we not be gritting? could you not be gritting? could they not be gritting?
Perfect
could I not have gritted? could you not have gritted? could he not have gritted? could we not have gritted? could you not have gritted? could they not have gritted?
V-ing perfect
could I not have been gritting? could you not have been gritting? could he not have been gritting? could we not have been gritting? could you not have been gritting? could they not have been gritting?