A man is sitting in an open mailbox.
The mailbox is open
The mailbox is open because there's a man sitting in it.
exists e1 s1 x1 x2.(in(e1,x2) & n_mailbox(x2) & a_open(s1) & Theme(s1,x2) & Actor(e1,x1) & v_sit(e1) & n_man(x1))
exists s1 x1.(n_mailbox(x1) & Theme(s1,x1) & a_open(s1))