I can backstop you can backstop he can backstop we can backstop you can backstop they can backstop
V-ing form
I can be backstoping you can be backstoping he can be backstoping we can be backstoping you can be backstoping they can be backstoping
Perfect
I can have backstoped you can have backstoped he 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 he can have been backstoping we can have been backstoping you can have been backstoping they can have been backstoping
Negation
Simple form
I can't backstop you can't backstop he can't backstop we can't backstop you can't backstop they can't backstop
V-ing form
I can't be backstoping you can't be backstoping he can't be backstoping we can't be backstoping you can't be backstoping they can't be backstoping
Perfect
I can't have backstoped you can't have backstoped he can't have backstoped we can't have backstoped you can't have backstoped they can't have backstoped
V-ing perfect
I can't have been backstoping you can't have been backstoping he can't have been backstoping we can't have been backstoping you can't have been backstoping they can't have been backstoping
Interrogative form
Simple form
can I backstop? can you backstop? can he backstop? can we backstop? can you backstop? can they backstop?
V-ing form
can I be backstoping? can you be backstoping? can he be backstoping? can we be backstoping? can you be backstoping? can they be backstoping?
Perfect
can I have backstoped? can you have backstoped? can he 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 he have been backstoping? can we have been backstoping? can you have been backstoping? can they have been backstoping?
Interro-negative form
Simple form
can't I backstop? can't you backstop? can't he backstop? can't we backstop? can't you backstop? can't they backstop?
V-ing form
can't I be backstoping? can't you be backstoping? can't he be backstoping? can't we be backstoping? can't you be backstoping? can't they be backstoping?
Perfect
can't I have backstoped? can't you have backstoped? can't he have backstoped? can't we have backstoped? can't you have backstoped? can't they have backstoped?
V-ing perfect
can't I have been backstoping? can't you have been backstoping? can't he have been backstoping? can't we have been backstoping? can't you have been backstoping? can't they have been backstoping?