Final answer:
When a dependent clause precedes an independent clause, a comma should be used to separate them. This applies when the subordinating conjunction of the dependent clause does not imply contrast.
Step-by-step explanation:
When a dependent clause comes before an independent clause, the correct punctuation to use is a comma. For example, in the sentence 'If you speak the truth, have a foot in the stirrup,' the subordinating conjunction 'if' indicates the beginning of the dependent clause, which is followed by a comma before the independent clause starts. Conversely, if the subordinating conjunction does not imply contrast, such as 'because' in the sentence 'He cancelled his magazine subscription because he thought the editors no longer addressed important issues,' a comma is not needed.