Two children are laughing in the grass.
One of the children just farted.
Two children laughing are not necessarily because one just farted.
exists e1 x1 x2.(n_grass(x2) & in(e1,x2) & Actor(e1,x1) & v_laugh(e1) & n_child(x1) & card_eq_2(x1))
exists e1 s1 x1 x2.(n_child(x2) & a_just(s1) & Manner(e1,s1) & Actor(e1,x1) & v_fart(e1) & of(x1,x2) & n_thing(x1) & card_eq_1(x1))