Someone in a red coat and white helmet skis past some trees.
A person in a red coat is following a person in a black coat on skis.
A person can be skiing without following a person in a black coat.
exists s1 s2 x1 x2 x3 x4 x5 x6.(a_topic(x1) & in(x1,x2) & subset_of(x4,x2) & past(x4,x6) & n_tree(x6) & n_ski(x4) & of(x4,x5) & n_helmet(x5) & a_white(s2) & Theme(s2,x4) & subset_of(x3,x2) & n_coat(x3) & a_red(s1) & Theme(s1,x3) & n_person(x1))
exists e1 s1 s2 x1 x2 x3 x4 x5.(on(e1,x5) & n_ski(x5) & Theme(e1,x3) & Actor(e1,x1) & v_follow(e1) & in(x3,x4) & n_coat(x4) & a_black(s2) & Theme(s2,x4) & n_person(x3) & in(x1,x2) & n_coat(x2) & a_red(s1) & Theme(s1,x2) & n_person(x1))