I could calk you could calk he could calk we could calk you could calk they could calk
V-ing form
I could be calking you could be calking he could be calking we could be calking you could be calking they could be calking
Perfect
I could have calked you could have calked he could have calked we could have calked you could have calked they could have calked
V-ing perfect
I could have been calking you could have been calking he could have been calking we could have been calking you could have been calking they could have been calking
Negation
Simple form
I could not calk you could not calk he could not calk we could not calk you could not calk they could not calk
V-ing form
I could not be calking you could not be calking he could not be calking we could not be calking you could not be calking they could not be calking
Perfect
I could not have calked you could not have calked he could not have calked we could not have calked you could not have calked they could not have calked
V-ing perfect
I could not have been calking you could not have been calking he could not have been calking we could not have been calking you could not have been calking they could not have been calking
Interrogative form
Simple form
could I calk? could you calk? could he calk? could we calk? could you calk? could they calk?
V-ing form
could I be calking? could you be calking? could he be calking? could we be calking? could you be calking? could they be calking?
Perfect
could I have calked? could you have calked? could he have calked? could we have calked? could you have calked? could they have calked?
V-ing perfect
could I have been calking? could you have been calking? could he have been calking? could we have been calking? could you have been calking? could they have been calking?
Interro-negative form
Simple form
could I not calk? could you not calk? could he not calk? could we not calk? could you not calk? could they not calk?
V-ing form
could I not be calking? could you not be calking? could he not be calking? could we not be calking? could you not be calking? could they not be calking?
Perfect
could I not have calked? could you not have calked? could he not have calked? could we not have calked? could you not have calked? could they not have calked?
V-ing perfect
could I not have been calking? could you not have been calking? could he not have been calking? could we not have been calking? could you not have been calking? could they not have been calking?