could stalk
Regular verb: stalk - stalked- stalked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could stalk
you could stalk
she could stalk
we could stalk
you could stalk
they could stalk 	I could be stalking
you could be stalking
she could be stalking
we could be stalking
you could be stalking
they could be stalking	I could have stalked
you could have stalked
she could have stalked
we could have stalked
you could have stalked
they could have stalked	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 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't stalk
you couldn't stalk
she couldn't stalk
we couldn't stalk
you couldn't stalk
they couldn't stalk 	I couldn't be stalking
you couldn't be stalking
she couldn't be stalking
we couldn't be stalking
you couldn't be stalking
they couldn't be stalking	I couldn't have stalked
you couldn't have stalked
she couldn't have stalked
we couldn't have stalked
you couldn't have stalked
they couldn't have stalked	I couldn't have been stalking
you couldn't have been stalking
she couldn't have been stalking
we couldn't have been stalking
you couldn't have been stalking
they couldn't have been stalking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I stalk?
could you stalk?
could she stalk?
could we stalk?
could you stalk?
could they stalk? 	could I be stalking?
could you be stalking?
could she be stalking?
could we be stalking?
could you be stalking?
could they be stalking? 	could I have stalked?
could you have stalked?
could she have stalked?
could we have stalked?
could you have stalked?
could they have stalked? 	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 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I stalk?
couldn't you stalk?
couldn't she stalk?
couldn't we stalk?
couldn't you stalk?
couldn't they stalk? 	couldn't I be stalking?
couldn't you be stalking?
couldn't she be stalking?
couldn't we be stalking?
couldn't you be stalking?
couldn't they be stalking? 	couldn't I have stalked?
couldn't you have stalked?
couldn't she have stalked?
couldn't we have stalked?
couldn't you have stalked?
couldn't they have stalked? 	couldn't I have been stalking?
couldn't you have been stalking?
couldn't she have been stalking?
couldn't we have been stalking?
couldn't you have been stalking?
couldn't they have been stalking?