Final answer:
Foreshadowing is a literary technique where an author gives subtle hints or clues about future events in a story.
Step-by-step explanation:
The subject of this question is English, specifically literature and foreshadowing. Foreshadowing is a literary technique where an author gives subtle hints or clues about future events in a story. In this case, if one character warns another character to be careful swimming in the ocean, it might foreshadow that a strong current may pose a hazard. The warning suggests that there may be dangerous conditions in the water that could potentially harm the swimmer.
Learn more about Foreshadowing in literature