I can prevent you can prevent he can prevent we can prevent you can prevent they can prevent
V-ing form
I can be preventing you can be preventing he can be preventing we can be preventing you can be preventing they can be preventing
Perfect
I can have prevented you can have prevented he can have prevented we can have prevented you can have prevented they can have prevented
V-ing perfect
I can have been preventing you can have been preventing he can have been preventing we can have been preventing you can have been preventing they can have been preventing
Negation
Simple form
I cannot prevent you cannot prevent he cannot prevent we cannot prevent you cannot prevent they cannot prevent
V-ing form
I cannot be preventing you cannot be preventing he cannot be preventing we cannot be preventing you cannot be preventing they cannot be preventing
Perfect
I cannot have prevented you cannot have prevented he cannot have prevented we cannot have prevented you cannot have prevented they cannot have prevented
V-ing perfect
I cannot have been preventing you cannot have been preventing he cannot have been preventing we cannot have been preventing you cannot have been preventing they cannot have been preventing
Interrogative form
Simple form
can I prevent? can you prevent? can he prevent? can we prevent? can you prevent? can they prevent?
V-ing form
can I be preventing? can you be preventing? can he be preventing? can we be preventing? can you be preventing? can they be preventing?
Perfect
can I have prevented? can you have prevented? can he have prevented? can we have prevented? can you have prevented? can they have prevented?
V-ing perfect
can I have been preventing? can you have been preventing? can he have been preventing? can we have been preventing? can you have been preventing? can they have been preventing?
Interro-negative form
Simple form
can I not prevent? can you not prevent? can he not prevent? can we not prevent? can you not prevent? can they not prevent?
V-ing form
can I not be preventing? can you not be preventing? can he not be preventing? can we not be preventing? can you not be preventing? can they not be preventing?
Perfect
can I not have prevented? can you not have prevented? can he not have prevented? can we not have prevented? can you not have prevented? can they not have prevented?
V-ing perfect
can I not have been preventing? can you not have been preventing? can he not have been preventing? can we not have been preventing? can you not have been preventing? can they not have been preventing?