Anytime that you are combining two simple sentences to write one complex sentence it will have a subordinate conjunction is this correct.

Example> The Lydians began the use of money in 700 B.C.before they invented coins.
The first sentence was The Lydians began the use of money in 700 B.C. They invented coins.

2 answers

Yes. You are correct. :)
Which one is the run-on sentence:

A) Don't run around.
B)after the store don't run around.
C)after the store.