そこ

1. Origins, structure, and basic meaning

• Structure: そこ directly refers to a place and combines with particles such as に or で.
• Basic usage: It points to a place near the listener.
  • そこに荷物を置いてください。 asks for luggage to be placed at a spot on the listener's side.

2. Common pitfalls and similar expressions

• Placement and activity
  • そこに置く marks where an object is to be placed, while そこで開ける marks where the activity of opening it takes place.
• A previously mentioned place
  • In 駅の前に店があります。そこで待ちます。, the second sentence refers back to the shop just introduced. In such contexts, physical distance from the listener alone does not determine the meaning.