I can backstop you can backstop she can backstop we can backstop you can backstop they can backstop
V-ing form
I can be backstoping you can be backstoping she can be backstoping we can be backstoping you can be backstoping they can be backstoping
Perfect
I can have backstoped you can have backstoped she can have backstoped we can have backstoped you can have backstoped they can have backstoped
V-ing perfect
I can have been backstoping you can have been backstoping she can have been backstoping we can have been backstoping you can have been backstoping they can have been backstoping
Negation
Simple form
I cannot backstop you cannot backstop she cannot backstop we cannot backstop you cannot backstop they cannot backstop
V-ing form
I cannot be backstoping you cannot be backstoping she cannot be backstoping we cannot be backstoping you cannot be backstoping they cannot be backstoping
Perfect
I cannot have backstoped you cannot have backstoped she cannot have backstoped we cannot have backstoped you cannot have backstoped they cannot have backstoped
V-ing perfect
I cannot have been backstoping you cannot have been backstoping she cannot have been backstoping we cannot have been backstoping you cannot have been backstoping they cannot have been backstoping
Interrogative form
Simple form
can I backstop? can you backstop? can she backstop? can we backstop? can you backstop? can they backstop?
V-ing form
can I be backstoping? can you be backstoping? can she be backstoping? can we be backstoping? can you be backstoping? can they be backstoping?
Perfect
can I have backstoped? can you have backstoped? can she have backstoped? can we have backstoped? can you have backstoped? can they have backstoped?
V-ing perfect
can I have been backstoping? can you have been backstoping? can she have been backstoping? can we have been backstoping? can you have been backstoping? can they have been backstoping?
Interro-negative form
Simple form
can I not backstop? can you not backstop? can she not backstop? can we not backstop? can you not backstop? can they not backstop?
V-ing form
can I not be backstoping? can you not be backstoping? can she not be backstoping? can we not be backstoping? can you not be backstoping? can they not be backstoping?
Perfect
can I not have backstoped? can you not have backstoped? can she not have backstoped? can we not have backstoped? can you not have backstoped? can they not have backstoped?
V-ing perfect
can I not have been backstoping? can you not have been backstoping? can she not have been backstoping? can we not have been backstoping? can you not have been backstoping? can they not have been backstoping?