A massive crowd is holding a flag.
people are swimming
A massive crowd implies a number of people in the magnitude of 100s or 1000s whereas people implies a smaller group. Holding a flag and swimming are mutually exclusive activities.
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_hold(e1) & n_flag(x2) & n_crowd(x1) & a_massive(s1) & Theme(s1,x1))
exists e1 x1.(Actor(e1,x1) & v_swim(e1) & n_people(x1))