A young girl works on homework at a table.
The girl works on homework
Sentence 1 specifies that the girl is working on her homework at a table, but sentence 2 simply states she's at work on homework without specifying a location.
exists e1 s1 x1 x2 x3.(at(e1,x3) & n_table(x3) & on(e1,x2) & n_homework(x2) & Actor(e1,x1) & v_work(e1) & n_girl(x1) & a_young(s1) & Theme(s1,x1))
exists e1 x1 x2.(n_girl(x1) & on(e1,x2) & n_homework(x2) & Actor(e1,x1) & v_work(e1))