Two construction workers wearing yellow rubber boots are sitting next to some pipes.
Two construction workers.
The second sentence just shows that there are two construction workers, which are also described in the first sentence.
exists e1 e2 s1 x1 x2 x3 x4 x5 x6.(to(e2,x6) & n_pipe(x6) & r_next(e2) & Actor(e2,x1) & v_sit(e2) & Theme(e1,x4) & Actor(e1,x3) & v_wear(e1) & n_boot(x4) & of(x4,x5) & n_rubber(x5) & a_yellow(s1) & Theme(s1,x4) & (x1 = x3) & n_worker(x1) & of(x1,x2) & n_construction(x2) & card_eq_2(x1))
exists s1 x1 x2.(n_worker(x1) & a_.(s1) & Theme(s1,x1) & of(x1,x2) & n_construction(x2) & card_eq_2(x1) & a_topic(x1))