Two person are riding their bicycles.
The two men are swimming.
Two person do not have to be men.  If people are riding bicycles they are not swimming.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_bicycle(x2) & of(x2,x1) & n_thing(x1) & n_person(x1) & card_eq_2(x1))
exists e1 x1.(n_man(x1) & card_eq_2(x1) & Actor(e1,x1) & v_swim(e1))