Some cows cluster together.
Some cows gather
Cows either cluster or gather together.
exists e1 p1 x1.(exists s1.(Theme(s1,x1) & a_together(s1)) & Topic(e1,p1) & Actor(e1,x1) & v_cluster(e1) & n_cow(x1))
exists e1 x1.(Actor(e1,x1) & v_gather(e1) & n_cow(x1))