The boat is white
The boat has a flag near the back.
Not every boat has a flag near the back.
exists s1 x1.(n_boat(x1) & Theme(s1,x1) & a_white(s1))
exists e1 x1 x2 x3.(n_back(x3) & n_boat(x1) & Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & near(x2,x3) & n_flag(x2))