A man holds a guitar on a busy street while people look on.
A man holds a tuba on an empty street.
The man can be holding either a tuba or a guitar. The street cannot be busy and empty at the same time. If there are people watching the man the street is not empty.
exists e1 p1 s1 x1 x2 x3.(exists e2 p2 x4.(exists s2.(Theme(s2,x4) & a_on(s2)) & Topic(e2,p2) & Actor(e2,x4) & v_look(e2) & n_people(x4)) & while(e1,p1) & Theme(e1,x2) & Actor(e1,x1) & v_hold(e1) & on(x2,x3) & n_street(x3) & a_busy(s1) & Theme(s1,x3) & n_guitar(x2) & n_man(x1))
exists e1 s1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_hold(e1) & on(x2,x3) & n_street(x3) & a_empty(s1) & Theme(s1,x3) & n_tuba(x2) & n_man(x1))