Several people are dancing in some sand.
The people know how to dance well.
Dancing does not imply they know how to dance well.
exists e1 s1 x1 x2.(in(e1,x2) & n_sand(x2) & Actor(e1,x1) & v_dance(e1) & n_people(x1) & a_several(s1) & Theme(s1,x1))
exists e1 x1 x2.(n_people(x1) & Topic(e1,x2) & Actor(e1,x1) & v_know(e1) & n_manner(x2) & exists e2 s1 x3.(a_well(s1) & Manner(e2,s1) & Actor(e2,x3) & v_dance(e2)))