A man is speaking at a podium.
The man is a professor, and is teaching biology class.
A man can speak at a podium without being a professor.    A man can speak at a podium without teaching a biology class.
exists e1 x1 x2.(at(e1,x2) & n_podium(x2) & Actor(e1,x1) & v_speak(e1) & n_man(x1))
exists e1 p1 s1 x1 x2.(n_man(x1) & Theme(e1,x2) & Actor(e1,x1) & v_teach(e1) & n_class(x2) & a_biology(s1) & Theme(s1,x2) & exists x3.((x1 = x3) & n_professor(x3)))