I can excuse you can excuse he can excuse we can excuse you can excuse they can excuse
V-ing form
I can be excusing you can be excusing he can be excusing we can be excusing you can be excusing they can be excusing
Perfect
I can have excused you can have excused he can have excused we can have excused you can have excused they can have excused
V-ing perfect
I can have been excusing you can have been excusing he can have been excusing we can have been excusing you can have been excusing they can have been excusing
Negation
Simple form
I can't excuse you can't excuse he can't excuse we can't excuse you can't excuse they can't excuse
V-ing form
I can't be excusing you can't be excusing he can't be excusing we can't be excusing you can't be excusing they can't be excusing
Perfect
I can't have excused you can't have excused he can't have excused we can't have excused you can't have excused they can't have excused
V-ing perfect
I can't have been excusing you can't have been excusing he can't have been excusing we can't have been excusing you can't have been excusing they can't have been excusing
Interrogative form
Simple form
can I excuse? can you excuse? can he excuse? can we excuse? can you excuse? can they excuse?
V-ing form
can I be excusing? can you be excusing? can he be excusing? can we be excusing? can you be excusing? can they be excusing?
Perfect
can I have excused? can you have excused? can he have excused? can we have excused? can you have excused? can they have excused?
V-ing perfect
can I have been excusing? can you have been excusing? can he have been excusing? can we have been excusing? can you have been excusing? can they have been excusing?
Interro-negative form
Simple form
can't I excuse? can't you excuse? can't he excuse? can't we excuse? can't you excuse? can't they excuse?
V-ing form
can't I be excusing? can't you be excusing? can't he be excusing? can't we be excusing? can't you be excusing? can't they be excusing?
Perfect
can't I have excused? can't you have excused? can't he have excused? can't we have excused? can't you have excused? can't they have excused?
V-ing perfect
can't I have been excusing? can't you have been excusing? can't he have been excusing? can't we have been excusing? can't you have been excusing? can't they have been excusing?