Several people having a good time while exercising.
Some people are enjoying exercising.
Several people are some people, and having a good time implies enjoying.
exists e2 e1 s1 s2 x1 x2 x3.(a_topic(x1) & while(e1,e2) & Actor(e2,x2) & v_exercise(e2) & Theme(e1,x3) & Actor(e1,x2) & v_have(e1) & n_time(x3) & a_good(s2) & Theme(s2,x3) & (x1 = x2) & n_people(x1) & a_several(s1) & Theme(s1,x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_enjoy(e1) & n_exercise(x2) & n_people(x1))