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 cannot focus you cannot focus he cannot focus we cannot focus you cannot focus they cannot focus
V-ing form
I cannot be focusing you cannot be focusing he cannot be focusing we cannot be focusing you cannot be focusing they cannot be focusing
Perfect
I cannot have focused you cannot have focused he cannot have focused we cannot have focused you cannot have focused they cannot have focused
V-ing perfect
I cannot have been focusing you cannot have been focusing he cannot have been focusing we cannot have been focusing you cannot have been focusing they cannot 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 I not focus? can you not focus? can he not focus? can we not focus? can you not focus? can they not focus?
V-ing form
can I not be focusing? can you not be focusing? can he not be focusing? can we not be focusing? can you not be focusing? can they not be focusing?
Perfect
can I not have focused? can you not have focused? can he not have focused? can we not have focused? can you not have focused? can they not have focused?
V-ing perfect
can I not have been focusing? can you not have been focusing? can he not have been focusing? can we not have been focusing? can you not have been focusing? can they not have been focusing?