A father and son at a Walmart.
They are shopping for gifts.
We don't know that the person is shopping.
exists s1 x1 x2 x3.(a_topic(s1) & subset_of(x2,s1) & at(x2,x3) & ne_org_walmart(x3) & n_son(x2) & subset_of(x1,s1) & n_father(x1))
exists e1 x1.(for(e1,x1) & n_gift(x1) & Actor(e1,x1) & v_shop(e1) & n_thing(x1))