The crowd watches the musher's dog sled.
The sled was destroyed in a fire 150 years ago.
They could not be watching a musher's sled if the sled was destroyed.
exists e2 e1 x1 x2 x3 x4.(n_dog(x3) & of(x3,x2) & n_musher(x2) & n_crowd(x1) & Theme(e2,x3) & Actor(e2,x1) & v_watch(e2) & Actor(e1,x4) & v_sled(e1) & (x3 = x4))
exists e1 x1 x2 x3.(n_sled(x1) & ago(e1,x3) & n_year(x3) & card_eq_150(x3) & in(e1,x2) & n_fire(x2) & Theme(e1,x1) & v_destroy(e1))