I can fool you can fool he can fool we can fool you can fool they can fool
V-ing form
I can be fooling you can be fooling he can be fooling we can be fooling you can be fooling they can be fooling
Perfect
I can have fooled you can have fooled he can have fooled we can have fooled you can have fooled they can have fooled
V-ing perfect
I can have been fooling you can have been fooling he can have been fooling we can have been fooling you can have been fooling they can have been fooling
Negation
Simple form
I cannot fool you cannot fool he cannot fool we cannot fool you cannot fool they cannot fool
V-ing form
I cannot be fooling you cannot be fooling he cannot be fooling we cannot be fooling you cannot be fooling they cannot be fooling
Perfect
I cannot have fooled you cannot have fooled he cannot have fooled we cannot have fooled you cannot have fooled they cannot have fooled
V-ing perfect
I cannot have been fooling you cannot have been fooling he cannot have been fooling we cannot have been fooling you cannot have been fooling they cannot have been fooling
Interrogative form
Simple form
can I fool? can you fool? can he fool? can we fool? can you fool? can they fool?
V-ing form
can I be fooling? can you be fooling? can he be fooling? can we be fooling? can you be fooling? can they be fooling?
Perfect
can I have fooled? can you have fooled? can he have fooled? can we have fooled? can you have fooled? can they have fooled?
V-ing perfect
can I have been fooling? can you have been fooling? can he have been fooling? can we have been fooling? can you have been fooling? can they have been fooling?
Interro-negative form
Simple form
can I not fool? can you not fool? can he not fool? can we not fool? can you not fool? can they not fool?
V-ing form
can I not be fooling? can you not be fooling? can he not be fooling? can we not be fooling? can you not be fooling? can they not be fooling?
Perfect
can I not have fooled? can you not have fooled? can he not have fooled? can we not have fooled? can you not have fooled? can they not have fooled?
V-ing perfect
can I not have been fooling? can you not have been fooling? can he not have been fooling? can we not have been fooling? can you not have been fooling? can they not have been fooling?