I.on [美 ɑn, ɔn, 英 ɒn]介词on often appears as the second element of certain verb structures in English (count on, lay on, sign on, etc). For translations, see the relevant verb entry (count, lay, sign, etc).
With patents' insurance information, we can figure out right on the spot which medicines are the best deal for them -- no more drugstore sticker shock.
After further searching, he remarked that his metal detector suddenly went doolally and that he knew for sure he was standing right on top of a crock of gold.