Let's learn something new!

1. On:

   • "On" is a preposition commonly used to indicate position or location in relation to a surface, point, or object.
   • Example: "The book is on the table." Here, "on" indicates the position of the book in relation to the surface of the table.
   • Example: "She placed her keys on the counter." In this sentence, "on" indicates the location of the keys in relation to the surface of the counter.

2. Upon:

   • "Upon" is also a preposition that can be used interchangeably with "on" in many contexts, particularly in formal or literary language.
   • Example: "Upon arrival, please check in at the front desk." Here, "upon arrival" indicates the point in time when the action of checking in should occur.
   • Example: "He found his wallet upon opening the drawer." In this sentence, "upon opening the drawer" indicates the point in time when he found his wallet.