The keyboard is white
A white keyboard in front of a computer
Not all keyboards are in front of a computer.
exists s1 x1.(n_keyboard(x1) & Theme(s1,x1) & a_white(s1))
exists s1 x1 x2 x3.(a_topic(x1) & in(x1,x2) & of(x2,x3) & n_computer(x3) & n_front(x2) & n_keyboard(x1) & a_white(s1) & Theme(s1,x1))