Man secures a large block of concrete.
A guy chains up concrete.
A block of concrete can be secured other than when someone chains up concrete.
exists e1 s1 x1 x2 x3.(ne_nam_man(x1) & Theme(e1,x2) & Actor(e1,x1) & v_secure(e1) & of(x2,x3) & n_concrete(x3) & n_block(x2) & a_large(s1) & Theme(s1,x2))
exists x1 x2 x3.(a_topic(x1) & up(x1,x3) & n_concrete(x3) & n_chain(x1) & of(x1,x2) & n_guy(x2))