A black Labrador retriever in a grassy field returns with a white nubby cylinder in its mouth.
A dog is practicing retrieving with it's master.
Just because a dog brings an object from its forays does not prove it is practicing retrieving with its master.
exists s1 s2 s3 s4 x1 x2 x3 x4 x5 x6.(a_topic(x1) & in(x1,x3) & with(x3,x5) & in(x5,x6) & n_mouth(x6) & of(x6,x1) & n_thing(x1) & n_cylinder(x5) & a_nubby(s4) & Theme(s4,x5) & a_white(s3) & Theme(s3,x5) & n_return(x3) & of(x3,x4) & n_field(x4) & a_grassy(s2) & Theme(s2,x3) & n_retriever(x1) & of(x1,x2) & n_labrador(x2) & a_black(s1) & Theme(s1,x1))
exists e1 p1 p2 x1 x2.(exists x3.((x1 = x3) & n_master(x3)) & exists e2.(with(e2,x1) & Actor(e2,x2) & v_retrieve(e2)) & n_thing(x1) & Topic(e1,p1) & Actor(e1,x2) & v_practice(e1) & (x1 = x2) & n_dog(x1))