I could calk you could calk she could calk we could calk you could calk they could calk
V-ing form
I could be calking you could be calking she could be calking we could be calking you could be calking they could be calking
Perfect
I could have calked you could have calked she 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 she could have been calking we could have been calking you could have been calking they could have been calking
Negation
Simple form
I couldn't calk you couldn't calk she couldn't calk we couldn't calk you couldn't calk they couldn't calk
V-ing form
I couldn't be calking you couldn't be calking she couldn't be calking we couldn't be calking you couldn't be calking they couldn't be calking
Perfect
I couldn't have calked you couldn't have calked she couldn't have calked we couldn't have calked you couldn't have calked they couldn't have calked
V-ing perfect
I couldn't have been calking you couldn't have been calking she couldn't have been calking we couldn't have been calking you couldn't have been calking they couldn't have been calking
Interrogative form
Simple form
could I calk? could you calk? could she calk? could we calk? could you calk? could they calk?
V-ing form
could I be calking? could you be calking? could she be calking? could we be calking? could you be calking? could they be calking?
Perfect
could I have calked? could you have calked? could she 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 she have been calking? could we have been calking? could you have been calking? could they have been calking?
Interro-negative form
Simple form
couldn't I calk? couldn't you calk? couldn't she calk? couldn't we calk? couldn't you calk? couldn't they calk?
V-ing form
couldn't I be calking? couldn't you be calking? couldn't she be calking? couldn't we be calking? couldn't you be calking? couldn't they be calking?
Perfect
couldn't I have calked? couldn't you have calked? couldn't she have calked? couldn't we have calked? couldn't you have calked? couldn't they have calked?
V-ing perfect
couldn't I have been calking? couldn't you have been calking? couldn't she have been calking? couldn't we have been calking? couldn't you have been calking? couldn't they have been calking?