A man plays the drums with a serious expression.
The man is playing the drums while making facial expressions.
Both sentences are referring to man playing the drums
exists e1 s1 x1 x2 x3.(n_drum(x2) & with(e1,x3) & n_expression(x3) & a_serious(s1) & Theme(s1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_man(x1))
exists e2 e1 s1 x1 x2 x3.(n_drum(x2) & n_man(x1) & while(e1,e2) & Theme(e2,x3) & Actor(e2,x1) & v_make(e2) & n_expression(x3) & a_facial(s1) & Theme(s1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1))