I could stalk you could stalk she could stalk we could stalk you could stalk they could stalk
V-ing form
I could be stalking you could be stalking she could be stalking we could be stalking you could be stalking they could be stalking
Perfect
I could have stalked you could have stalked she could have stalked we could have stalked you could have stalked they could have stalked
V-ing perfect
I could have been stalking you could have been stalking she could have been stalking we could have been stalking you could have been stalking they could have been stalking
Negation
Simple form
I could not stalk you could not stalk she could not stalk we could not stalk you could not stalk they could not stalk
V-ing form
I could not be stalking you could not be stalking she could not be stalking we could not be stalking you could not be stalking they could not be stalking
Perfect
I could not have stalked you could not have stalked she could not have stalked we could not have stalked you could not have stalked they could not have stalked
V-ing perfect
I could not have been stalking you could not have been stalking she could not have been stalking we could not have been stalking you could not have been stalking they could not have been stalking
Interrogative form
Simple form
could I stalk? could you stalk? could she stalk? could we stalk? could you stalk? could they stalk?
V-ing form
could I be stalking? could you be stalking? could she be stalking? could we be stalking? could you be stalking? could they be stalking?
Perfect
could I have stalked? could you have stalked? could she have stalked? could we have stalked? could you have stalked? could they have stalked?
V-ing perfect
could I have been stalking? could you have been stalking? could she have been stalking? could we have been stalking? could you have been stalking? could they have been stalking?
Interro-negative form
Simple form
could I not stalk? could you not stalk? could she not stalk? could we not stalk? could you not stalk? could they not stalk?
V-ing form
could I not be stalking? could you not be stalking? could she not be stalking? could we not be stalking? could you not be stalking? could they not be stalking?
Perfect
could I not have stalked? could you not have stalked? could she not have stalked? could we not have stalked? could you not have stalked? could they not have stalked?
V-ing perfect
could I not have been stalking? could you not have been stalking? could she not have been stalking? could we not have been stalking? could you not have been stalking? could they not have been stalking?