What's better? Stuffing your savings into a mattress, or investing it in a profitable venture? Obviously, the thought of having your money work for you is appealing. Lots of Russians felt the same way and so bought shares in MMM – Russia's greatest financial fraud of the 90s. And as crazy as it sounds, many people out there are still investing in a "sure thing", just like our dialog's hero. In today's grammar, we'll take a closer look at the prepositional case — its usage and its most common ending.