A woman in a black skirt is reading a book on the subway.
A woman is solving math problems with a fork.
Reading a book can't be done while solving math problems. You can only focus on one thing at a time.
exists e1 s1 x1 x2 x3 x4.(n_subway(x4) & Theme(e1,x3) & Actor(e1,x1) & v_read(e1) & on(x3,x4) & n_book(x3) & in(x1,x2) & n_skirt(x2) & a_black(s1) & Theme(s1,x2) & n_woman(x1))
exists e1 x1 x2 x3 x4.(Theme(e1,x2) & Actor(e1,x1) & v_solve(e1) & with(x2,x4) & n_fork(x4) & n_problem(x2) & of(x2,x3) & n_math(x3) & n_woman(x1))