I'm taking an intermediate Chinese course and ran across a character whose usage I can't quite wrap my head around: 就.
I believe the meaning of the character itself are "then, right away, etc." However, I'm finding it difficult to really understand the usage from just the definition itself. Here is an example from the textbook I'm using:
等你来天津， 我就给你当导游。 (When you come to Tianjin, I'll give you a tour.)
等你来天津， 我给你当导游。(When you come to Tianjin, I'll be your guide.)
How should I interpret 就 in this context?