A man with glasses is at the dentist.
A man is with a toothache is at the dentist.
There is nothing to indicate he is at the dentist because of a toothache.
exists p1 x1 x2 x3.(n_dentist(x3) & at(x1,x3) & with(x1,x2) & n_glass(x2) & n_man(x1))
exists p1 x1 x4.(n_dentist(x4) & exists p2 x2 x3.(with(x1,x2) & at(x3,x4) & (x2 = x3) & n_toothache(x2)) & n_man(x1))