I can preexist you can preexist he can preexist we can preexist you can preexist they can preexist
V-ing form
I can be preexisting you can be preexisting he can be preexisting we can be preexisting you can be preexisting they can be preexisting
Perfect
I can have preexisted you can have preexisted he can have preexisted we can have preexisted you can have preexisted they can have preexisted
V-ing perfect
I can have been preexisting you can have been preexisting he can have been preexisting we can have been preexisting you can have been preexisting they can have been preexisting
Negation
Simple form
I cannot preexist you cannot preexist he cannot preexist we cannot preexist you cannot preexist they cannot preexist
V-ing form
I cannot be preexisting you cannot be preexisting he cannot be preexisting we cannot be preexisting you cannot be preexisting they cannot be preexisting
Perfect
I cannot have preexisted you cannot have preexisted he cannot have preexisted we cannot have preexisted you cannot have preexisted they cannot have preexisted
V-ing perfect
I cannot have been preexisting you cannot have been preexisting he cannot have been preexisting we cannot have been preexisting you cannot have been preexisting they cannot have been preexisting
Interrogative form
Simple form
can I preexist? can you preexist? can he preexist? can we preexist? can you preexist? can they preexist?
V-ing form
can I be preexisting? can you be preexisting? can he be preexisting? can we be preexisting? can you be preexisting? can they be preexisting?
Perfect
can I have preexisted? can you have preexisted? can he have preexisted? can we have preexisted? can you have preexisted? can they have preexisted?
V-ing perfect
can I have been preexisting? can you have been preexisting? can he have been preexisting? can we have been preexisting? can you have been preexisting? can they have been preexisting?
Interro-negative form
Simple form
can I not preexist? can you not preexist? can he not preexist? can we not preexist? can you not preexist? can they not preexist?
V-ing form
can I not be preexisting? can you not be preexisting? can he not be preexisting? can we not be preexisting? can you not be preexisting? can they not be preexisting?
Perfect
can I not have preexisted? can you not have preexisted? can he not have preexisted? can we not have preexisted? can you not have preexisted? can they not have preexisted?
V-ing perfect
can I not have been preexisting? can you not have been preexisting? can he not have been preexisting? can we not have been preexisting? can you not have been preexisting? can they not have been preexisting?