A boy with glasses on is sitting in a chair at the dentist.
a boy is sitting on the chair at the dentist
'  sitting in a chair at the dentist ' is a rephrasing of  ' sitting on the chair at the dentist .'
exists e1 s1 x1 x2 x3 x4 x5.(n_dentist(x5) & at(e1,x5) & in(e1,x4) & n_chair(x4) & Actor(e1,x1) & v_sit(e1) & with(x1,x2) & Theme(s1,x3) & a_on(s1) & (x2 = x3) & n_glass(x2) & n_boy(x1))
exists e1 x1 x2 x3.(n_dentist(x3) & n_chair(x2) & at(e1,x3) & on(e1,x2) & Actor(e1,x1) & v_sit(e1) & n_boy(x1))