I can focus you can focus he can focus we can focus you can focus they can focus
V-ing form
I can be focusing you can be focusing he can be focusing we can be focusing you can be focusing they can be focusing
Perfect
I can have focused you can have focused he can have focused we can have focused you can have focused they can have focused
V-ing perfect
I can have been focusing you can have been focusing he can have been focusing we can have been focusing you can have been focusing they can have been focusing
Negation
Simple form
I can't focus you can't focus he can't focus we can't focus you can't focus they can't focus
V-ing form
I can't be focusing you can't be focusing he can't be focusing we can't be focusing you can't be focusing they can't be focusing
Perfect
I can't have focused you can't have focused he can't have focused we can't have focused you can't have focused they can't have focused
V-ing perfect
I can't have been focusing you can't have been focusing he can't have been focusing we can't have been focusing you can't have been focusing they can't have been focusing
Interrogative form
Simple form
can I focus? can you focus? can he focus? can we focus? can you focus? can they focus?
V-ing form
can I be focusing? can you be focusing? can he be focusing? can we be focusing? can you be focusing? can they be focusing?
Perfect
can I have focused? can you have focused? can he have focused? can we have focused? can you have focused? can they have focused?
V-ing perfect
can I have been focusing? can you have been focusing? can he have been focusing? can we have been focusing? can you have been focusing? can they have been focusing?
Interro-negative form
Simple form
can't I focus? can't you focus? can't he focus? can't we focus? can't you focus? can't they focus?
V-ing form
can't I be focusing? can't you be focusing? can't he be focusing? can't we be focusing? can't you be focusing? can't they be focusing?
Perfect
can't I have focused? can't you have focused? can't he have focused? can't we have focused? can't you have focused? can't they have focused?
V-ing perfect
can't I have been focusing? can't you have been focusing? can't he have been focusing? can't we have been focusing? can't you have been focusing? can't they have been focusing?