Two people are wearing giant sombreros.
The people wear giant sombreros for cinco de mayo.
The first sentence does not indicate that the people are wearing the giant sombreros for cinco de mayo.  They could be wearing the giant sombreros for any other reason.
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_wear(e1) & n_sombrero(x2) & a_giant(s1) & Theme(s1,x2) & n_people(x1) & card_eq_2(x1))
exists e1 s1 s2 x1 x2 x3 x4.(n_people(x1) & for(e1,x3) & n_mayo(x3) & a_de(s2) & Theme(s2,x3) & of(x3,x4) & n_cinco(x4) & Theme(e1,x2) & Actor(e1,x1) & v_wear(e1) & n_sombrero(x2) & a_giant(s1) & Theme(s1,x2))