This man studies the controls while working with heavy machinery.
This man studies the controls
sentence 1 is adding more details "while working with heavy machinery.  "
exists e2 e1 s1 x1 x2 x3.(n_control(x2) & n_man(x1) & while(e1,e2) & with(e2,x3) & n_machinery(x3) & a_heavy(s1) & Theme(s1,x3) & Actor(e2,x1) & v_work(e2) & Theme(e1,x2) & Actor(e1,x1) & v_study(e1))
exists e1 x1 x2.(n_control(x2) & n_man(x1) & Theme(e1,x2) & Actor(e1,x1) & v_study(e1))