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 couldn't grit you couldn't grit he couldn't grit we couldn't grit you couldn't grit they couldn't grit
V-ing form
I couldn't be gritting you couldn't be gritting he couldn't be gritting we couldn't be gritting you couldn't be gritting they couldn't be gritting
Perfect
I couldn't have gritted you couldn't have gritted he couldn't have gritted we couldn't have gritted you couldn't have gritted they couldn't have gritted
V-ing perfect
I couldn't have been gritting you couldn't have been gritting he couldn't have been gritting we couldn't have been gritting you couldn't have been gritting they couldn't 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
couldn't I grit? couldn't you grit? couldn't he grit? couldn't we grit? couldn't you grit? couldn't they grit?
V-ing form
couldn't I be gritting? couldn't you be gritting? couldn't he be gritting? couldn't we be gritting? couldn't you be gritting? couldn't they be gritting?
Perfect
couldn't I have gritted? couldn't you have gritted? couldn't he have gritted? couldn't we have gritted? couldn't you have gritted? couldn't they have gritted?
V-ing perfect
couldn't I have been gritting? couldn't you have been gritting? couldn't he have been gritting? couldn't we have been gritting? couldn't you have been gritting? couldn't they have been gritting?