A young boy is playing the trumpet at a concert.
A young boy is playing at his first concert.
Just because, the young boy is playing the trumpet at a concert, does not mean it is his first concert.
exists e1 s1 x1 x2 x3.(n_trumpet(x2) & at(e1,x3) & n_concert(x3) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_boy(x1) & a_young(s1) & Theme(s1,x1))
exists e1 s1 s2 x1 x2.(at(e1,x2) & n_concert(x2) & a_first(s2) & Theme(s2,x2) & of(x2,x1) & n_male(x1) & Actor(e1,x1) & v_play(e1) & n_boy(x1) & a_young(s1) & Theme(s1,x1))